P. K. Patil^a, Dr. D. B. Salunkhe^b*, Dr. H. S. Gavale^c*

^aDept. Of Physics, S.S.V.P.S’s L. K. Dr. P. R. Ghogrey Science College, Dhule

^bDepartment of Physics, KVPS Kisan ACS College Parola Dist Jalgaon 425111

^c Dept Of Physics, Z. B. Patil College, Dhule

Abstract:
The production of semiconductor materials which are lead free and eco-friendly has become a more focus of research into sustainable and renewable energy. The need for safe, eco-friendly and sustainable solar energy materials has increased interest in lead-free photovoltaic technologies. Silver bismuth chalcogenides, namely AgBiS₂ and AgBiSe₂, are promising absorber materials because they are environmentally friendly, chemically stable, and made from relatively abundant elements. These materials have suitable band gaps, absorb light strongly, and can tolerate crystal defects, which are important for efficient solar cell performance. AgBiS₂ and AgBiSe₂ thin films can be produced using low-cost and scalable methods such as spin coating, successive ionic layer adsorption and reaction (SILAR), hydrothermal synthesis, and other solution-based techniques. These methods are suitable for large-area and flexible solar devices. In addition, AgBiS₂ and AgBiSe₂ show better thermal and environmental stability compared to lead-based perovskite materials. This review summarizes recent progress in their synthesis, structural and optical properties, and photovoltaic performance. The main challenges, including charge transport and interface losses, are discussed, along with future research directions to improve efficiency and long-term stability.

Keywords:AgBiX₂, AgBiS₂, AgBiSe₂, eco-friendly, lead-free chalcogenides, photovoltaics, sustainable energy, solar devices.

1.Introduction:

The rising global demand for energy and increasing environmental concerns have intensified research into renewable energy sources. Solar energy is considered one of the most promising options because it is clean, abundant, and sustainable [1,2]. However, conventional silicon-based solar cells involve high-temperature processing and costly manufacturing steps, which limit their economic feasibility for large-scale deployment [3]. This has motivated the search for alternative photovoltaic materials that are efficient, low-cost, and environmentally benign [4,5].

Lead-based perovskite solar cells have demonstrated rapid improvements in power conversion efficiency in recent years [6,7]. Despite this progress, their commercial application is hindered by the presence of toxic lead and poor long-term stability under moisture, heat, and continuous light exposure [8–10]. These issues have driven significant efforts toward the development of lead-free photovoltaic materials with improved environmental safety and operational stability [11,12].

Chalcogenide semiconductors have emerged as attractive candidates for lead-free solar cells due to their high optical absorption, tunable band gaps, and good chemical stability [13–15]. Among them, silver bismuth chalcogenides, particularly AgBiS₂ and AgBiSe₂, have received growing attention as sustainable absorber materials [9-13]. These compounds consist of relatively non-toxic and earth-abundant elements and possess band gap energies well suited for solar energy conversion [8-12]. Their strong light absorption enables efficient photon harvesting in thin films, while their defect-tolerant nature helps suppress non-radiative recombination losses [2].

AgBiS₂ and AgBiSe₂ are also compatible with low-cost and scalable fabrication techniques, including spin coating, successive ionic layer adsorption and reaction (SILAR), and hydrothermal synthesis [14]. These solution-based methods allow large-area deposition and integration with flexible substrates [9]. In addition, silver bismuth chalcogenides exhibit improved thermal and environmental stability compared to lead-based perovskite materials, making them promising for long-term photovoltaic applications [8].

This review presents an overview of recent progress in AgBiS₂ and AgBiSe₂-based photovoltaic materials, covering synthesis routes, structural, optical, and electrical properties, and device performance [10,11]. Key challenges related to charge transport, interface engineering, and efficiency optimization are discussed, and future research directions are proposed to advance stable, efficient, and environmentally friendly solar cell technologies [11].

2. Properties and Crystal Structure:
1. Crystal Structure

AgBiS₂ and AgBiSe₂ are ternary chalcogenide semiconductors composed of silver, bismuth, and sulfur or selenium. These materials generally crystallize in a cubic or near-cubic crystal structure, which is favorable for uniform thin-film formation [1,2]. In the crystal lattice, Ag⁺ and Bi³⁺ ions occupy metal sites and are coordinated by S²⁻ or Se²⁻ anions [3].

Their atomic arrangement resembles a rock-salt-type framework, where metal–chalcogen bonds form a compact and symmetric network [4]. This structural symmetry allows the materials to accommodate a certain level of lattice disorder without severe degradation of electronic properties [5]. Such defect tolerance is particularly beneficial for solution-processed films, where perfect crystallinity is difficult to achieve [6].

2. Optical and Electrical Properties

AgBiS₂ and AgBiSe₂ exhibit strong absorption in the visible region, with absorption coefficients high enough to enable efficient light harvesting in thin absorber layers [7,8]. AgBiS₂ mainly absorbs visible light, while AgBiSe₂ has a slightly narrower band gap, allowing absorption to extend into the near-infrared region [9,10].

1. Optical Absorption Behaviour

AgBiX₂ (X = S, Se) materials show strong light absorption in the visible and near-infrared (NIR) regions, which is essential for efficient solar energy harvesting. UV–Vis absorption studies typically reveal a clear and sharp absorption edge, indicating good crystallinity and a well-defined electronic band structure. These materials possess high absorption coefficients in the range of about 10²–10⁵ cm⁻¹, allowing effective photon absorption even with very thin films. This property is particularly beneficial for low-cost and flexible photovoltaic devices.

Replacing sulfur (S) with selenium (Se) causes the absorption edge to shift toward longer wavelengths. This red shift occurs due to the larger atomic size and higher polarizability of selenium. As a result, the material can absorb a broader portion of the solar spectrum, improving light utilization in photovoltaic applications.

• Band Gap Energy

The optical band gap (Eg) of AgBiX₂ compounds is commonly determined using Tauc plots derived from UV–Vis absorption measurements. These materials typically exhibit direct or quasi-direct band gap characteristics, which are advantageous for optoelectronic and photovoltaic applications.

AgBiS₂ generally shows a band gap in the range of 1.2 to 1.6 eV. In comparison, AgBiSe₂ has a smaller band gap, usually between 0.9 and 1.2 eV. This reduction in band gap allows AgBiSe₂ to absorb light over a wider wavelength range.

Both band gap values fall close to the optimal range required for efficient solar energy conversion, enabling effective utilization of the solar spectrum [2–3]. Furthermore, the band gap of these materials can be tuned through anion substitution (S to Se), nanostructure formation, and defect engineering, enhancing their suitability for photovoltaic devices.

• Photoluminescence (PL) Characteristics

Photoluminescence analysis provides valuable insight into charge carrier recombination processes and the presence of defects in AgBiX₂ materials. These compounds generally show weak to moderate PL emission, which indicates reduced radiative recombination and efficient separation of photo-generated charge carriers. Such behavior is highly desirable for applications in solar cells and photocatalysis.

The observed PL emission peaks are commonly attributed to recombination occurring near the band edge as well as defect-related states, including sulfur or selenium vacancies and antisite defects. Lower PL intensity suggests suppressed electron–hole recombination, which contributes to improved photovoltaic and photocatalytic performance [6].

Electrical Properties and Charge Transport:

Electrical characterization reveals that AgBiX₂ materials generally show p-type conductivity, primarily arising from intrinsic defects such as silver vacancies [1,2]. Synthesis conditions and post-deposition treatments have a strong influence on charge carrier concentration, mobility, and electrical resistivity [3,4]. Enhanced crystallinity and reduced defect density improve charge transport and suppress recombination losses, resulting in improved electrical performance [5–7]Both compounds behave as semiconductors and show effective generation of charge carriers under illumination [11]. Their electronic structure supports the transport of electrons and holes with relatively low recombination losses. Importantly, AgBiS₂ and AgBiSe₂ are known for their defect-tolerant nature, where common point defects do not form deep trap states that severely limit carrier lifetime.

3. Thermal and Environmental Stability

A major advantage of AgBiS₂ and AgBiSe₂ is their high thermal and environmental stability compared to lead-based perovskite absorbers [12,13]. These materials retain their structural and optical properties when exposed to air, moisture, and moderate heating conditions [7].

The strong metal–chalcogen bonds in silver bismuth chalcogenides provide chemical robustness, reducing the risk of phase degradation or decomposition during long-term operation [18,19]. Several studies have reported stable performance of AgBiS₂ and AgBiSe₂ thin films under continuous light exposure and extended storage periods [20–22]. This stability makes them suitable candidates for durable and reliable photovoltaic devices.

In summary, AgBiS₂ and AgBiSe₂ possess favorable crystal structures, strong optical absorption, suitable band gaps, and defect-tolerant electronic properties [21,22]. Their excellent resistance to thermal and environmental degradation further enhances their potential as lead-free absorber materials for sustainable photovoltaic applications [15-18].

3.1Chemical Synthesis Approaches for AgBiS₂ and AgBiSe₂ Thin Films:

1. Successive Ionic Layer Adsorption and Reaction (SILAR)

SILAR is a solution-based deposition technique that is widely applied for the preparation of AgBiS₂ and AgBiSe₂ thin films because of its simplicity and low processing cost [1,2]. The method involves repeated dipping of the substrate into cationic and anionic solutions, separated by rinsing steps. Silver and bismuth ions are adsorbed from metal salt solutions, followed by reaction with sulfur or selenium ions to form the chalcogenide layer on the substrate surface [3].

The thickness and composition of the films can be adjusted by controlling the number of deposition cycles, solution concentration, and immersion time [4]. Doping can be conveniently introduced by adding suitable dopant ions into the metal precursor solution, allowing easy modification of the film properties without complex processing steps [5,6]. Due to its low-temperature operation and suitability for large substrates, SILAR is well suited for cost-effective photovoltaic fabrication.

2. Chemical Bath Deposition (CBD)

Chemical bath deposition is a commonly used technique for producing chalcogenide semiconductor films with uniform coverage [7]. In this method, the substrate is placed in a reaction bath containing metal precursors, a sulfur or selenium source, and complexing agents that regulate the release of ions into the solution [8]. Controlled chemical reactions in the bath lead to gradual film growth on the substrate.

Film quality, including thickness, grain size, and stoichiometry, can be tailored by varying parameters such as bath temperature, pH, and deposition duration [9]. Doping is achieved by introducing small amounts of dopant salts into the bath, enabling uniform incorporation during film growth [10,11]. Post-deposition heat treatment is often applied to improve crystallinity and electrical performance [12].

3. Hydrothermal Method

The hydrothermal method involves chemical reactions carried out in sealed vessels at elevated temperature and pressure [13]. This approach allows the synthesis of AgBiS₂ and AgBiSe₂ materials with high crystallinity and controlled morphology [14]. Metal salts and chalcogen sources are dissolved in aqueous or mixed solvents and heated under carefully controlled conditions.

Dopant elements can be added directly to the precursor solution, leading to uniform dopant distribution throughout the material [15,16]. Although hydrothermal synthesis produces high-quality materials, its use in large-area thin-film deposition is limited. Therefore, it is mainly employed for nanostructured absorbers and fundamental material studies.

4. Spin Coating of TiO₂ Base Layer

Spin coating is a widely adopted technique for depositing compact and uniform TiO₂ layers that act as electron transport layers in photovoltaic devices [17]. A TiO₂ precursor solution or diluted paste is dropped onto the substrate and spread evenly by rapid rotation [18].

The final film thickness is influenced by the spin speed, spinning time, and solution viscosity [19]. After coating, thermal treatment is usually applied to enhance film densification and charge transport properties [20]. A well-prepared TiO₂ base layer improves interfacial contact and facilitates efficient electron extraction from AgBiS₂ or AgBiSe₂ absorber layers [21,22].

In summary, SILAR and CBD are particularly effective for depositing doped AgBiS₂ and AgBiSe₂ thin films using low-cost and scalable solution-based techniques. The hydrothermal method provides high-quality crystalline materials but is less suitable for large-area films. Spin coating remains an efficient and reliable approach for preparing TiO₂ base layers, contributing to improved photovoltaic device performance

3.3 Post-Deposition Treatments and Performance Enhancement

After film deposition, additional processing steps are often required to improve the quality and performance of AgBiS₂ and AgBiSe₂ thin films. These post-deposition treatments help enhance crystal structure, reduce defects, and improve charge transport within the photovoltaic device [1,2].

A) Heat Treatment (Annealing)

Heat treatment is widely applied to improve the structural properties of AgBiS₂ and AgBiSe₂ films [3]. Annealing is typically performed in air, inert atmospheres, or sulfur- or selenium-rich environments. This process allows atoms within the film to rearrange into a more ordered structure, leading to larger grain sizes and improved crystallinity [4].

Annealing also removes residual solvents and improves film compactness, which enhances electrical conductivity and reduces carrier recombination [5]. However, excessive heating may cause chalcogen loss or phase instability, making careful optimization of annealing conditions essential [6].

B) Sulfurization and Selenization Treatments

Exposure of deposited films to sulfur or selenium vapor is commonly used to correct compositional deficiencies and improve phase quality [7]. Such treatments help compensate for sulfur or selenium vacancies that can form during film growth [8].

By reducing these vacancies, carrier transport properties are improved, resulting in enhanced photovoltaic performance [9]. Chalcogen-rich treatments are particularly beneficial for films prepared by solution-based methods, where slight non-stoichiometry is often observed [10].

C)Surface and Interface Modification

Surface treatments are important for minimizing charge losses caused by surface defects [11]. Chemical passivation techniques can reduce dangling bonds and surface trap states, leading to improved carrier lifetime [12].Engineering the interface between AgBiS₂/AgBiSe₂ absorber layers and the TiO₂ electron transport layer is also crucial. Improved interface quality enhances charge transfer and suppresses interfacial recombination, contributing to higher device efficiency [13,14].

D) Post-Treatment of TiO₂ Base Layer

The performance of the TiO₂ base layer can be significantly improved through post-deposition treatment [19]. Thermal annealing enhances TiO₂ crystallinity and electron mobility, while surface treatments reduce trap states at the TiO₂ surface [20].

An optimized TiO₂ layer provides better electronic contact with the absorber material, enabling efficient electron extraction and reducing recombination losses at the interface [21,22].

4.Morphological and Structural Characteristics

AgBiS₂ and AgBiSe₂ thin films generally exhibit smooth and well-covered surfaces with uniform grain distribution when prepared using solution-based techniques. Optimized deposition conditions and post-deposition heat treatment promote grain growth, resulting in fewer grain boundaries that support improved charge transport. The film thickness typically lies in the sub-micron to micron range, providing effective and uniform light absorption across the absorber layer. Structural studies, such as X-ray diffraction, confirm that these materials commonly crystallize in cubic or near-cubic phases. Thermal treatment further enhances crystallinity and phase stability. A reduced density of structural defects contributes to better electrical transport properties. Together, these morphological and structural features play a crucial role in achieving efficient and stable photovoltaic device performance.

7Applications for Sustainable Energy

Silver bismuth chalcogenides such as AgBiS₂ and AgBiSe₂ are increasingly explored for sustainable energy applications because they are free from toxic lead, absorb light efficiently, and show good operational stability [1,2]. Their suitable band gap energies make them effective light-absorbing layers for thin-film solar cells [3]. In addition, these materials can be deposited using inexpensive and scalable solution-based techniques, allowing the fabrication of large-area and flexible photovoltaic devices [4].

Beyond solar cells, AgBiX₂ materials have demonstrated potential in photocatalytic processes, including solar-driven water splitting and the breakdown of environmental pollutants, due to their strong visible-light response and effective charge carrier separation [5,6]. Their chemical robustness supports stable performance under prolonged illumination [7]. Overall, silver bismuth chalcogenides offer a promising and environmentally friendly pathway for advancing next-generation sustainable energy technologies [8–10].

8Problems and Future Prospects

Despite the significant progress achieved with AgBiX₂ materials, several challenges still need to be addressed. These include achieving precise control over material stoichiometry, suppressing the formation of secondary phases, and ensuring long-term device stability. Improving performance further will require effective strategies such as controlled doping, interface engineering, and defect passivation. Future research should focus on developing scalable fabrication methods and gaining a deeper understanding of defect-related physics, which are essential steps toward the commercial realization of AgBiX₂-based energy devices.

9.Conclusion

Silver bismuth chalcogenides, namely AgBiS₂ and AgBiSe₂, have gained considerable attention as lead-free materials for sustainable energy applications. Their suitable band gap energies, strong optical absorption, defect-tolerant behavior, and good thermal and environmental stability make them highly promising for use in photovoltaic and photocatalytic systems. Moreover, these materials can be synthesized using low-cost and scalable solution-based methods, enabling their application in large-area devices. With further advancements in controlled synthesis, doping techniques, and interface engineering, the performance of AgBiS₂ and AgBiSe₂ is expected to improve further, strengthening their potential as environmentally friendly alternatives for next-generation solar energy technologies.

References

1. Solution Deposition of High-Quality AgBiS₂Thin Films via a Binary Diamine-Dithiol Solvent System — Mehri Ghasemi et al., Materials Science & Technology (2025). Reports high absorption coefficients (~10²–10³ cm⁻¹) and a favorable bandgap (~1.3 eV) for AgBiS₂ thin films. Scilight Press
2. Thermally Co-Evaporated Ternary Chalcogenide AgBiS₂ Thin Films for Photovoltaic Applications — M. Choi et al., J. Mater. Chem. A (2024). Focuses on synthesis and optical absorption behavior of AgBiS₂ films grown by thermal co-evaporation. RSC Publishing
3. Recent Advances of AgBiS₂: Synthesis Methods, Photovoltaic Device, Photodetector, and Sensors — Zongwei Li et al., Electromagnetic Science (2025). Reviews optical and optoelectronic properties including absorption, bandgap, and stability. EM Science
4. Advancements in AgBiS₂ Thin Film Solar Cells: Strategies, Challenges, and Perspectives — Aryan Maurya et al., JPhys Energy (2025). Highlights intrinsic optical properties (tunable bandgap & high absorption) of AgBiS₂ absorber layers in TFSCs. Northumbria Research Portal
5. Evolution of the Formation of AgBiS₂ Colloidal Nanocrystals for Optoelectronic Devices — F. A. Nur Mawaddah et al., Nanoscale (2025). Discusses optical absorption behavior of AgBiS₂ nanocrystals relevant to photodetector and PV technologies. RSC Publishing
6. Cation-Exchange Synthesis of AgBiS₂and AgBiSe₂ Quantum Dots — (2025 publication, Elsevier). Paper on synthesis and optical behavior (absorption, size-dependent band edges) of chalcogenide QDs. ScienceDirect
7. Review on the Optical and Electrical Properties of Chalcogenide Thin Films: Challenges and Applications — W. A. Abd El-Ghany, Phys. Chem. Chem. Phys. (2025). Comprehensive thin-film optical property overview (UV–Vis absorption, band gap control techniques). RSC Publishing
8. Review: AgBiS₂ for Green Optoelectronics (From Material Design to Devices) — ScienceDirect Review (2025). Summarizes optical characteristics (tunable bandgap, light absorption) and device performance of AgBiS₂. ScienceDirect
9. Ligand-Tuned AgBiS₂ Planar Heterojunctions Enable Efficient Photovoltaics — ACS Nano (2024). Although focused on device performance, includes analysis of absorption and bandgap modulation via ligand engineering. ACS Publications
10. Nanocrystal AgBiS₂ Optical Absorption and Structure — Various ResearchGate posts and related conference abstracts (2025). Contains measured absorption spectra and electronic transitions in AgBiS₂ samples. ResearchGate
11.  Brandt, R. E., et al., “Investigation of AgBiS₂ as a Lead-Free Photovoltaic Absorber,”J. Phys. Chem. Lett., 2015, 6, 4297–4302.
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Nishigandha Piran Borase

Sau. Rajanitai Nanasaheb Deshmukh

Arts, Commerce & Science College, Bhadgaon Dist. Jalgaon

gmail – nishigandhaborase@gmail.com

Abstract :-

Contemporary research increasingly requires cooperation among different academic disciplines to address multifaceted social, technological, and economic challenges. In this context, quantitative methods provide a reliable and systematic foundation for integrating diverse perspectives. This paper analyses the significance of numerical and analytical techniques in interdisciplinary research and examines their contribution to knowledge development, policy formulation, and innovation. The study highlights the importance of strengthening quantitative competence to enhance the quality and effectiveness of research in the 21^st century.

Keywords :-

Interdisciplinary Studies, Quantitative Techniques, Statistical Analysis, Mathematical Models, Data Analytics, Higher Education, Management.

Introduction :-

Modern society is characterized by rapid scientific progress, digital transformation, and increasing global interdependence. Contemporary problems such as environmental sustainability, economic development, public health, and educational reforms are complex and interconnected in nature. These challenges cannot be effectively addressed within the boundaries of a single discipline.

Interdisciplinary research offers an integrated approach by combining theories, methods, and tools from multiple fields. Within this framework, quantitative approaches play a crucial role by ensuring accuracy, consistency and objectivity in research outcomes. This paper discusses how quantitative techniques strengthen interdisciplinary research and support evidence-based decision-making.

Nature and Scope of Interdisciplinary Research :-

Interdisciplinary research refers to the systematic integration of knowledge from different academic domains in order to solve complex problems. It encourages collaboration among researchers and promotes intellectual exchange across disciplinary boundaries.

Unlike traditional disciplinary studies, interdisciplinary research emphasizes synthesis and mutual interaction. It aims to generate comprehensive perspectives and innovative solutions. In recent years, universities, funding agencies, and policy institutions have increasingly promoted such collaborative research practices.

Significance of Quantitative Methods :-

Quantitative methods provide a common analytical framework that facilitates communication among diverse disciplines. Their major contributions include the following,

1. Objectivity :-

Numerical data and standardized procedures reduce personal bias and enhance the credibility of research findings.

• Analytical Precision :-

Quantitative tools enable accurate measurement and detailed examination of relationships among variables.

• Validity and Generalization :-

Statistical techniques support the verification of results and allow conclusions to be extended to broader populations.

• Prediction and Evaluation :-

Mathematical and computational models assist researchers in forecasting trends and assessing alternative strategies.

Quantitative Tools and Analytical Techniques :-

1. Statistical Analysis :-

Statistical methods form the backbone of quantitative research. They include measures of central tendency, dispersion, correlation, regression, and hypothesis testing. These techniques help in summarizing data and drawing meaningful inferences.

• Mathematical Modeling :-

Mathematical models represent real-world systems using symbolic expressions and equations. They are widely used in economics, social sciences, environmental studies, and engineering to analyze dynamic processes.

• Data Analytics and Computational Methods :-

The availability of large-scale digital data has increased the importance of data analytics. Techniques such as machine learning, artificial intelligence, and visualization tools assist in extracting useful patterns from complex datasets.

• Optimization and Decision Models :-

Operations research techniques, including linear programming, network analysis, and game theory, support efficient resource allocation and strategic planning in interdisciplinary projects.

Interdisciplinary Applications of Quantitative Approaches :-

1. Scientific Research and Technology :-

In scientific investigations, quantitative techniques support experimental design, simulation, and validation of results. They enhance precision and reproducibility in research processes.

• Educational Studies :-

In education, numerical analysis is used to evaluate learning outcomes, teaching effectiveness, and institutional performance. These methods contribute to evidence-based educational planning.

• Business and Management :-

Quantitative approaches assist in financial forecasting, market analysis, risk assessment, and operational management. They improve strategic decision-making in commercial organizations.

• Social Sciences and Humanities :-

Social researchers increasingly apply statistical and computational tools for survey analysis, demographic studies, and behavioural research. Digital humanities also employ quantitative methods for textual and cultural analysis.

Framework for Quantitative Interdisciplinary Research :-

Interdisciplinary quantitative research generally follows a structured sequence of activities,

1. Identification and formulation of research problems.
2. Collection of data from multiple disciplinary sources.
3. Application of appropriate analytical techniques.
4. Interpretation and integration of results.
5. Development of practical recommendations and innovations.
6. This systematic framework ensures methodological rigor and transparency.

Challenges and Limitations :-

Despite its advantages, interdisciplinary quantitative research faces several difficulties,

1. Differences in conceptual frameworks and terminology.
2. Inadequate training in advanced quantitative methods.
3. Problems related to data availability and compatibility.
4. Ethical issues concerning privacy and confidentiality.
5. Limited institutional support for collaborative projects.

Addressing these limitations requires capacity-building programs, interdisciplinary curricula, and supportive research policies.

Emerging Trends and Future Prospects :-

The future of interdisciplinary research is closely associated with developments in artificial intelligence, big data, and digital research infrastructure. Increasing emphasis on open data platforms and international collaboration is expected to enhance global research networks.

Higher education institutions should promote integrated learning models that combine domain knowledge with quantitative skills. Such initiatives will prepare researchers to address emerging global challenges more effectively.

Conclusion :-

Quantitative approaches serve as a fundamental pillar of interdisciplinary research in the modern era. By providing systematic, objective, and reliable analytical tools, they facilitate the integration of knowledge across science, humanities, commerce, and education. Strengthening quantitative literacy and fostering collaborative environments are essential for improving research quality and societal impact in the 21^st century.

References :-

1. Klein, J. T. (2010) – A Taxonomy of Interdisciplinary, Oxford University Press, Page No. 45-78.
2. Creswell, J. W. (2014) – Research Design : Qualitative, Quantitative and Mixed Methods Approaches. Sage Publications, Page No. 201-245.
3. OECD (2017) – Interdisciplinary Research and Innovation, OECD Publishing, Page No. 112-146.
4. Shmueli, G., et al. (2020) – Data Mining for Business Analytics, Wiley, Page No. 89-134.
5. Government of India (2020) – National Education Policy. Ministry of Education, New Delhi, Page No. 34-58.                                     

Bhushan B. Chaudhari^1,3, Navnath M. Yajgar¹, Bharat G. Thakare¹, Niranjan S. Samudre¹, Rajendra R. Ahire¹,Amol R Naikda^1,2, Dhananjay S Patil⁴_,Nanasaheb P. Huse³, Sudam D. Chavhan^1*

¹Department of Physics, Vidya Vikas Mandal’s Sitaram Govind Patil ASC College, Sakri, Dhule, Maharashtra, India

²Department of Physics S.S.V.P. S’s L.K.Dr. P.R.Ghogrey Science College Dhule, Maharashtra, India

³Department of Physics, Nandurbar Taluka Vidhayak Samiti’s G. T. Patil Arts, Commerce and Science College, Nandurbar, Maharashtra, India

⁴Department of Zoology, Nandurbar Taluka Vidhayak Samiti’s G. T. Patil Arts, Commerce and Science College, Nandurbar, Maharashtra, India

*Corresponding Author: sudam1578@gmail.com

Abstract

Antimony sulfide (Sb2S3) has emerged as a promising earth-abundant and environmentally benign semiconductor for next-generation thin-film photovoltaic and optoelectronic applications [1].The material exhibits a suitable bandgap, high optical absorption coefficient, and excellent chemical stability, making it a strong candidate for low-cost solar energy conversion technologies [2].Unlike conventional chalcogenide absorbers such as CdTe and CIGS, Sb2S3 does not rely on toxic or scarce elements, which significantly improves its sustainability profile [3].Sb2S3 crystallizes in an orthorhombic structure composed of quasi-one-dimensional (Sb2S3) ribbon chains, resulting in highly anisotropic electrical and optical properties [4].These anisotropic characteristics strongly influence charge transport, defect formation, and device performance in thin-film solar cells [5].In recent years, extensive research efforts have been dedicated to controlling the morphology, crystallinity, and orientation of Sb2S3 thin films to overcome efficiency limitations [6].Various deposition techniques, including chemical bath deposition, spin coating, atomic layer deposition, spray pyrolysis, and thermal evaporation, have been systematically explored to optimize film quality [7].Furthermore, interface engineering, defect passivation, elemental doping, and post-treatment strategies have enabled significant improvements in power conversion efficiency [8].This review critically summarizes the fundamental structural and optoelectronic properties of Sb2S3 and correlates them with thin-film growth mechanisms and device performance [9].Special emphasis is placed on recent advances in Sb2S3-based solar cell architectures and performance optimization strategies [10].Finally, the remaining challenges and future research directions required for the commercialization of Sb2S3 thin-film technologies are discussed [11].

Keywords:Sb2S3 thin films; chalcogenide semiconductors; photovoltaic materials; solar cells.

1. Introduction

The continuous growth of global energy demand, coupled with the environmental impact of fossil fuel consumption, has intensified the search for sustainable and renewable energy technologies [12].Among various renewable energy sources, solar energy is considered the most abundant and universally accessible, with the potential to meet global energy requirements if efficiently harvested [13].Photovoltaic (PV) technologies play a central role in converting solar radiation directly into electrical energy, driving extensive research on advanced semiconductor materials [14].Conventional thin-film solar cell technologies, such as cadmium telluride (CdTe) and copper indium gallium selenide (CIGS), have demonstrated high power conversion efficiencies exceeding 22% [15].However, the large-scale deployment of these technologies is constrained by toxicity concerns, elemental scarcity, and high fabrication costs [16].As a result, earth-abundant and environmentally friendly absorber materials have attracted significant scientific and technological interest [17].Antimony sulfide (Sb2S3) is a binary chalcogenide semiconductor belonging to the A₂B₃ family (A = Sb, Bi; B = S, Se) and has emerged as a promising alternative absorber material [18].Sb2S3 exhibits a direct bandgap in the range of 1.6–1.8 eV, which is well suited for efficient absorption of visible solar radiation [19].The material also possesses a high absorption coefficient on the order of 10⁴–10⁵ cm⁻¹, enabling effective light harvesting with ultrathin absorber layers [20].

In addition to its favorable optical properties, Sb2S3 demonstrates good chemical stability under ambient conditions and resistance to moisture-induced degradation [21].These features make Sb2S3 particularly attractive for low-cost and scalable photovoltaic applications [22].Structurally, Sb2S3 crystallizes in an orthorhombic phase composed of one-dimensional ribbon-like (Sb2S3)ₙ chains extending along the crystallographic c-axis [23].The strong covalent bonding within these ribbons and weak van der Waals interactions between adjacent chains lead to pronounced anisotropy in charge transport properties [24].Such anisotropic behavior significantly influences carrier mobility, recombination dynamics, and defect formation in Sb2S3 thin films [25].Consequently, the orientation and morphology of Sb2S3 crystals play a crucial role in determining device performance [26].Understanding the relationship between crystal structure, thin-film growth, and photovoltaic behavior is therefore essential for the rational design of high-efficiency Sb2S3 solar cells [27].Sb2S3-based solar cells typically adopt device architectures similar to semiconductor-sensitized or planar heterojunction solar cells [28].These architectures commonly consist of a transparent conducting oxide, an electron transport layer, the Sb2S3 absorber, a hole transport material, and a metallic back contact [29].Despite a theoretically predicted efficiency exceeding 25%, experimentally reported efficiencies of Sb2S3 solar cells remain below 8% [30].The discrepancy between theoretical and experimental performance is primarily attributed to defect-induced recombination, poor carrier extraction, and sub-optimal interfaces [31].

Recent research has therefore focused on improving film quality, reducing trap density, and optimizing interfacial energetics [32].This review provides a comprehensive and critical analysis of Sb2S3 thin-film materials, emphasizing structure–property–performance relationships [33].The discussion begins with fundamental structural and optoelectronic properties of Sb2S3, followed by an overview of major thin-film deposition techniques [34].

Recent progress in device engineering, defect passivation, and performance enhancement strategies is systematically examined [35].By consolidating current knowledge and identifying key challenges, this review aims to guide future research toward highly efficient and commercially viable Sb2S3-based photovoltaic technologies [36].

(Schematic illustration of the quasi-one-dimensional crystal structure of Sb2S3 showing (a) the side view and top perspective of the orthorhombic lattice, and (b) the arrangement of [Sb₄S₆] ribbon units extending along the crystallographic c-axis, highlighting strong intra-ribbon bonding and weak inter-ribbon interactions that govern anisotropic physical properties [8, 23, 244].)

2. Crystal Structure and Fundamental Properties of Sb2S3

2.1 Crystal Structure of Antimony Sulfide (Sb2S3)

Antimony sulfide (Sb2S3) crystallizes in a thermodynamically stable orthorhombic phase with the space group Pnma under ambient conditions [37].The crystal lattice is characterized by lattice parameters a ≈ 11.3 Å, b ≈ 3.8 Å, and c ≈ 11.2 Å, indicating a highly anisotropic unit cell geometry [38].The fundamental structural motif of Sb2S3 consists of quasi-one-dimensional (Sb₄S₆)ₙ ribbon-like chains that extend parallel to the crystallographic c-axis [39].Within each ribbon, antimony atoms are coordinated with sulfur atoms through strong covalent bonds, forming a robust backbone for charge transport [40].Adjacent ribbons are held together by weak van der Waals interactions, resulting in easy cleavage along planes perpendicular to the b-axis [41].

The anisotropic bonding nature leads to directional dependence of mechanical, electrical, and optical properties in Sb2S3 crystals [42].Charge carriers preferentially transport along the ribbon direction due to reduced effective mass and stronger orbital overlap [43].In contrast, carrier transport perpendicular to the ribbon direction is hindered by weak inter-chain interactions, leading to reduced conductivity [44].This intrinsic anisotropy plays a decisive role in determining thin-film orientation and device efficiency [45].Experimental studies have demonstrated that Sb2S3 thin films with preferential orientation along the (hk0) planes exhibit improved photovoltaic performance [46].Such orientation facilitates efficient charge transport from the absorber to the charge-selective contacts [47].Therefore, controlling thecrystallographic orientation during film growth is a critical requirement for high-efficiency Sb2S3-based devices [48].

Orthorhombic crystal structure of Sb2S3 illustrating one-dimensional (Sb₄S₆)ₙ ribbon chains along the c-axis and weak inter-chain interactions. [8, 23, 244]

2.2 Electronic Band Structure and Anisotropy

Sb2S3 is a semiconductor with a bandgap that lies in the optimal range for single-junction solar cell applications [49].At room temperature, crystalline Sb2S3 exhibits a direct bandgap with reported values ranging from 1.6 to 1.8 eV depending on film quality and crystallinity [50].Amorphous Sb2S3 films, in contrast, often exhibit an indirect bandgap due to structural disorder and localized defect states [51].The conduction band minimum is primarily composed of Sb 5p orbitals, while the valence band maximum arises mainly from hybridized Sb 5s and S 3p orbitals [52].Density functional theory calculations reveal strong dispersion of electronic bands along the ribbon direction and relatively flat bands perpendicular to it [53].This anisotropic band dispersion results in direction-dependent effective masses for electrons and holes [54].Lower effective mass along the ribbon axis enables higher carrier mobility, which is beneficial for charge extraction in thin-film devices [55].However, misaligned crystal orientation in polycrystalline films can severely limit carrier transport and increase recombination losses [56].The electronic anisotropy of Sb2S3 also affects defect formation energies and trap-state distributions [57].Sulfur vacancies and antimony antisite defects introduce deep-level trap states within the bandgap [58].These trap states act as recombination centers, reducing carrier lifetime and open-circuit voltage in photovoltaic devices [59].Consequently, defect control and passivation strategies are essential for achieving high-performance Sb2S3 solar cells [60].

Conceptual energy band diagram of Sb2S3 illustrating direction-dependent electronic dispersion, with enhanced band curvature along the quasi-one-dimensional ribbon (c-axis) direction and comparatively reduced dispersion perpendicular to the ribbon chains, reflecting anisotropic charge transport behavior [23, 245, 246].

2.3 Optical Properties

Sb2S3 exhibits a high optical absorption coefficient exceeding 10⁵ cm⁻¹ in the visible region, enabling strong light absorption within thicknesses below 500 nm [61].The absorption onset closely corresponds to the bandgap energy, confirming the suitability of Sb2S3 as a thin-film absorber [62].Optical absorption is strongly influenced by crystallinity, grain size, and defect density in the film [63].Highly crystalline films exhibit sharper absorption edges and reduced sub-bandgap absorption associated with defect states [64].The absorption spectrum of Sb2S3 spans the visible to near-infrared region, allowing efficient utilization of the solar spectrum [65].Film thickness optimization is crucial, as excessively thick films increase recombination losses while thin films may result in incomplete light harvesting [66].Therefore, achieving an optimal balance between absorption depth and carrier diffusion length is critical for device design [67].

Representative optical absorption profile of Sb2S3 thin films demonstrating intense absorption across the visible spectral region and a distinct absorption onset corresponding to the fundamental band-edge transition, indicating efficient photon harvesting capability [6, 18, 245].

2.4 Electrical and Charge Transport Properties

Sb2S3 thin films typically exhibit n-type conductivity under ambient conditions [68].The electrical conductivity of Sb2S3 is relatively low at room temperature, primarily due to limited carrier concentration and mobility [69].Carrier mobility is strongly direction-dependent, with significantly higher values along the ribbon direction [70].Experimental measurements indicate that resistivity along the ribbon axis can be two orders of magnitude lower than that perpendicular to it [71].Temperature-dependent conductivity studies reveal thermally activated charge transport mechanisms in Sb2S3 [72].At elevated temperatures, increased carrier excitation enhances electrical conductivity [73].Doping and defect engineering have been widely explored to increase carrier concentration and reduce resistive losses [74].However, excessive doping can introduce additional trap states and structural disorder [75].The interplay between crystal structure, defect chemistry, and transport anisotropy ultimately governs the performance of Sb2S3-based optoelectronic devices [76].A comprehensive understanding of these properties is essential for optimizing thin-film growth and device architecture [77].

Current density–voltage (J–V) characteristics of Sb2S3 solar cell devices fabricated using varying concentrations of SbCl₃ precursor, illustrating the influence of precursor concentration on photovoltaic parameters such as open-circuit voltage, short-circuit current density, fill factor, and overall power conversion efficiency [18, 124, 203].

3. Thin-Film Deposition Techniques for Sb2S3

3.1 Importance of Deposition Technique Selection

The performance of Sb2S3 thin-film devices is strongly governed by the deposition technique employed for absorber layer fabrication [78].Deposition parameters directly influence film thickness, crystallinity, grain orientation, defect density, and interfacial quality [79].Due to the anisotropic crystal structure of Sb2S3, growth conditions play a critical role in determining ribbon alignment and charge transport pathways [80].Consequently, a wide range of physical and chemical deposition techniques have been explored to achieve high-quality Sb2S3 thin films [81].Each technique offers distinct advantages and limitations in terms of scalability, cost, and film quality [82].

3.2 Chemical Bath Deposition (CBD)

Chemical bath deposition is one of the most widely used low-temperature techniques for the synthesis of Sb2S3 thin films [83].In CBD, substrates are immersed in an aqueous solution containing antimony precursors, sulfur sources, and complexing agents [84].Controlled release of Sb³⁺ and S²⁻ ions lead to heterogeneous nucleation and growth of Sb2S3 on the substrate surface [85].CBD allows uniform coating over large areas and is compatible with low-cost and flexible substrates [86].The deposition temperature typically remains below 100 °C, making CBD suitable for temperature-sensitive substrates [87].However, CBD-grown Sb2S3 films often suffer from poor crystallinity and high defect density due to slow nucleation kinetics [88].Post-deposition annealing is commonly required to improve crystallinity and induce phase transformation from amorphous to crystalline Sb2S3 [89].Optimization of bath composition, pH, and deposition time has been shown to significantly enhance film quality and device performance [90].

3.3 Spin Coating Technique

Spin coating is a solution-based deposition technique widely adopted for laboratory-scale fabrication of Sb2S3 thin films [91].In this method, a precursor solution containing antimony and sulfur compounds is dispensed onto a rotating substrate [92].Centrifugal force spreads the solution uniformly, forming a thin liquid film that subsequently undergoes solvent evaporation [93].Thermal annealing is required to decompose the precursor and form crystalline Sb2S3 [94].Spin coating enables precise control over film thickness through adjustment of solutionconcentration and spin speed [95]. The technique is simple, rapid, and suitable for studying composition–property relationships [96].However, spin-coated films often exhibit pinholes and non-uniform coverage over large areas [97].Multiple coating–annealing cycles are frequently employed to improve film continuity [98].

3.4 Atomic Layer Deposition (ALD)

Atomic layer deposition is a vapor-phase technique based on sequential, self-limiting surface reactions [99].ALD offers atomic-level thickness control and excellent conformality, making it highly suitable for nanostructured substrates [100].Sb2S3 films deposited by ALD exhibit superior thickness uniformity and controlled stoichiometry [101].The technique allows deposition at relatively low temperatures, reducing thermal stress and interdiffusion at interfaces [102].ALD-grown Sb2S3 films demonstrate improved crystallinity and reduced defect density compared to solution-processed films [103].However, the deposition rate of ALD is relatively slow, and precursor availability can be a limiting factor [104].Despite these challenges, ALD remains a powerful tool for high-quality absorber layer fabrication and interface engineering [105].

3.5 Spray Pyrolysis Technique

Spray pyrolysis is a scalable and cost-effective technique for depositing Sb2S3 thin films over large areas [106].In this method, a precursor solution is atomized and sprayed onto a heated substrate [107].Thermal decomposition of the precursor droplets leads to the formation of Sb2S3 thin films [108].Film properties can be tuned by adjusting substrate temperature, spray rate, and solution concentration [109].Spray-deposited Sb2S3 films generally exhibit good adhesion and moderate crystallinity [110].However, controlling film uniformity and stoichiometry remains challenging due to rapid solvent evaporation [111].Optimized spray pyrolysis conditions have yielded promising photovoltaic performance [112].

3.6 Thermal Evaporation

Thermal evaporation is a physical vapor deposition technique widely used for high-purity Sb2S3 thin-film fabrication [113].In this method, Sb2S3 powder is heated under high vacuum until evaporation occurs, followed by condensation on a substrate [114].Thermal evaporation enables precise control over film thickness and composition [115].The resulting films often exhibit high crystallinity and low impurity levels [116].Substrate temperature during deposition significantly affects grain size and orientation [117].Post-deposition annealing further enhances crystal quality and reduces defect density [118].Despite higher equipment costs, thermal evaporation remains a preferred method for high-performance Sb2S3 solar cells [119].

3.7 Comparative Assessment of Deposition Techniques

Each deposition technique presents a unique balance between film quality, scalability, and cost [120].Solution-based methods offer low-cost processing but require extensive optimization to reduce defects [121].Vapor-phase techniques generally yield superior film quality at the expense of higher processing costs [122].Selecting an appropriate deposition method is therefore crucial for targeted applications and large-scale commercialization [123].

4. Sb2S3-Based Solar Cell Architectures and Device Physics

4.1 Overview of Sb2S3 Photovoltaic Device Architectures

Sb2S3 thin films have been extensively investigated as absorber layers in heterojunction solar cell architectures [124].The most commonly reported device configurations are derived from semiconductor-sensitized and planar heterojunction concepts [125].These architectures typically consist of a transparent conducting oxide, an electron transport layer, the Sb2S3 absorber, a hole transport material, and a metallic back contact [126].The choice of device architecture plays a critical role in determining charge separation efficiency and recombination dynamics [127].Early Sb2S3 solar cells were developed using mesoporous TiO₂ scaffolds to facilitate electron extraction [128].Such architectures benefited from large interfacial area but suffered from increased recombination losses due to poor pore filling [129].Subsequently, planar heterojunction architectures gained attention owing to their simpler structure and reduced recombination pathways [130].Recent studies have demonstrated that planar devices exhibit improved open-circuit voltage and fill factor compared to mesoporous counterparts [131].

Schematic representation of a conventional Sb2S3-based solar cell illustrating the layered device configuration comprising a glass substrate, fluorine-doped tin oxide (FTO) transparent electrode, electron transport layer, Sb2S3 absorber film, hole transport material, and metallic back contact, highlighting the charge-selective junctions within the device [124, 126, 130].

4.2 Electron Transport Layers and Interface Engineering

Electron transport layers (ETLs) play a crucial role in extracting photogenerated electrons from the Sb2S3 absorber [132].Commonly used ETLs include TiO₂, ZnO, SnO₂, and compact metal oxide layers [133].The conduction band alignment between Sb2S3 and the ETL strongly influences charge injection efficiency [134].An optimal conduction band offset minimizes energy barriers while suppressing interfacial recombination [135].Surface states and lattice mismatch at the ETL/Sb2S3 interface often introduce trap-assisted recombination centers [136].

Interface engineering techniques, such as surface passivation and buffer layer insertion, have been shown to significantly enhance device performance [137].Atomic layer deposited ETLs typically exhibit superior interfacial quality compared to solution-processed layers [138].Reducing interface defect density is essential for improving short-circuit current density and open-circuit voltage [139].

4.3 Hole Transport Materials and Back Contacts

Efficient extraction of photogenerated holes requires suitable hole transport materials (HTMs) with proper valence band alignment [140].Organic HTMs such as P3HT and Spiro-OMeTAD have been widely employed in Sb2S3 solar cells [141].Inorganic HTMs, including CuSCN, NiOₓ, and MoOₓ, have attracted attention due to their improved thermal and chemical stability [142].The choice of HTM significantly affects device stability and long-term performance [143].Back contact materials must provide low-resistance electrical contact while maintaining chemical compatibility with the absorber [144].Gold, silver, and carbon-based electrodes have been commonly utilized in Sb2S3 devices [145].Carbon electrodes offer cost advantages and improved stability compared to noble metals [146].

4.4 Charge Generation, Transport, and Recombination Mechanisms

Upon illumination, photons with energy exceeding the bandgap of Sb2S3 generate electron–hole pairs within the absorber layer [147].Efficient separation of photogenerated carriers requires strong built-in electric fields at the heterojunction interfaces [148].Electrons are transported toward the ETL, while holes migrate toward the HTM and back contact [149].Carrier transport efficiency is strongly influenced by crystal orientation, grain boundaries, and defect density [150].Trap-assisted recombination at grain boundaries and interfaces represents a major loss mechanism in Sb2S3 solar cells [151].Deep-level defect states capture charge carriers and reduce carrier lifetime [152].Minimizing recombination losses through defect passivation is therefore critical for enhancing power conversion efficiency [153].

4.5 Energy Band Alignment and Built-In Potential

Energy band alignment at the ETL/Sb2S3 and Sb2S3/HTM interfaces governs charge extraction efficiency [154].A favorable band alignment facilitates selective transport of electrons and holes while blocking opposite carriers [155].Improper alignment can lead to energy barriers that hinder carrier extraction and reduce fill factor [156].The built-in potential across the device arises from the difference in work functions of the contact materials [157].This internal electric field drives charge separation and suppresses bulk recombination [158].Engineering band alignment through material selection and interfacial modification has proven effective in improving device performance [159].

4.6 Photovoltaic Performance Metrics

Key performance parameters of Sb2S3 solar cells include open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency [160].The relatively low open-circuit voltage of Sb2S3 devices is primarily attributed to high recombination rates and deep-level defects [161].Enhancing crystallinity and reducing defect density have been shown to significantly improve voltage output [162].Recent reports demonstrate power conversion efficiencies approaching 8% through combined material and interface optimization strategies [163].

5. Recent Advances and Performance Enhancement Strategies in Sb2S3 Solar Cells

5.1 Defect Engineering and Passivation Strategies

Intrinsic and extrinsic defects play a dominant role in limiting the performance of Sb2S3-based solar cells [164].Sulfur vacancies, antimony antisite defects, and interstitial states introduce deep-level trap states within the bandgap [165].These trap states act as non-radiative recombination centers, significantly reducing carrier lifetime and open-circuit voltage [166].Defect passivation has therefore emerged as a critical strategy for improving device efficiency [167].Surface passivation using chalcogen-rich treatments has been shown to effectively suppress sulfur vacancy formation [168].Post-deposition sulfurization treatments reduce deep trap density and enhance crystallinity [169].Chemical treatments employing thiourea, Na₂S, and other sulfur-containing compounds have demonstrated notable improvements in photovoltaic performance [170].Passivated Sb2S3 films exhibit reduced sub-bandgap absorption and enhanced photoluminescence intensity [171].

5.2 Doping and Alloying Approaches

Controlled doping has been explored as a means to tailor the electronic properties of Sb2S3 thin films [172].Incorporation of alkali metals such as sodium and potassium has been shown to modify grain growth and defect chemistry [173].Doping-induced enhancement in carrier concentration improves electrical conductivity and charge extraction efficiency [174].However, excessive doping can lead to increased disorder and additional recombination pathways [175].Alloying Sb2S3 with selenium to form Sb₂(S,Se)₃ solid solutions has attracted significant attention [176].Partial substitution of sulfur with selenium allows bandgap tuning and improved carrier transport [177].Alloyed absorbers often exhibit enhanced crystallinity and reduced defect density compared to pure Sb2S3 [178].This approach has resulted in improved short-circuit current density and overall device efficiency [179].

5.3 Interface Engineering and Buffer Layer Optimization

Interface recombination represents one of the most critical loss mechanisms in Sb2S3 solar cells [180].Lattice mismatch and chemical incompatibility between Sb2S3 and transport layers often introduce interface trap states [181].Insertion of ultra-thin buffer layers has been demonstrated to significantly reduce interfacial recombination [182].Materials such as ZnS, In₂S₃, and organic interlayers have been employed as effective buffer layers [183].Buffer layers improve band alignment and suppress carrier back-transfer across interfaces [184].Atomic layer deposited buffer layers provide superior conformality and defect passivation [185].Optimized interface engineering leads to simultaneous improvements in open-circuit voltage and fill factor [186].

.5.4 Morphology Control and Grain Orientation Engineering

Film morphology and grain orientation critically influence charge transport and recombination behavior in Sb2S3 thin films [187].Larger grain size reduces the density of grain boundaries, which are major recombination centers [188].Thermal annealing under controlled atmosphere promotes grain growth and crystallographic alignment [189].Preferential orientation of ribbon chains perpendicular to the substrate enhances vertical carrier transport [190].Solvent engineering and precursor chemistry optimization have been shown to significantly improve film uniformity [191].Highly oriented films exhibit enhanced carrier mobility and reduced series resistance [192].Morphology-controlled Sb2S3 films demonstrate improved device reproducibility and stability [193].

5.5 Device Stability and Environmental Robustness

Long-term stability is a key requirement for commercial photovoltaic technologies [194].Sb2S3 exhibits superior environmental stability compared to many emerging absorber materials [195].The absence of volatile organic components in inorganic Sb2S3 devices contributes to improved thermal stability [196].Encapsulated Sb2S3 solar cells have demonstrated stable performance under prolonged illumination and humidity exposure [197].Degradation mechanisms primarily arise from interfacial diffusion and contact degradation [198].Use of inorganic hole transport layers and carbon-based electrodes significantly enhances device durability [199].Improved stability further strengthens the case for Sb2S3 as a viable absorber for sustainable photovoltaics [200].

5.6 Performance Trends and Efficiency Progress

Significant progress has been made in improving the efficiency of Sb2S3 solar cells over the past decade [201].Early devices exhibited power conversion efficiencies below 2% due to poor film quality and interface losses [202].Recent advances in deposition control, defect passivation, and interface engineering have enabled efficiencies approaching 8% [203].Despite these improvements, there remains a substantial gap between experimental efficiencies and theoretical limits [204].

6. Challenges, Limitations, and Future Research Directions

6.1 Fundamental Challenges in Sb2S3 Thin-Film Solar Cells

Despite significant progress, Sb2S3-based solar cells still face several fundamental challenges that limit their efficiency and commercial viability [205].One of the primary limitations is the relatively low open-circuit voltage compared to the theoretical maximum predicted for Sb2S3 absorbers [206].This voltage deficit is mainly attributed to high non-radiative recombination losses caused by deep-level defect states [207].Intrinsic defects such as sulfur vacancies and antimony antisite defects are difficult to eliminate completely during thin-film growth [208].Another major challenge arises from the anisotropic crystal structure of Sb2S3, which leads to direction-dependent charge transport [209].In polycrystalline thin films, random crystal orientation often results in inefficient vertical carrier transport toward charge-selective contacts [210].This structural anisotropy complicates device optimization and necessitates precise control over crystal growth orientation [211].Achieving uniform and preferential ribbon alignment over large areas remains a significant materials engineering challenge [212].

6.2 Interface-Related Losses and Contact Instability

Interface recombination at the ETL/Sb2S3 and Sb2S3/HTM interfaces continues to be a dominant loss mechanism [213].Lattice mismatch, interfacial defects, and unfavorable band alignment contribute to increased carrier recombination [214].Chemical instability at the back contact interface can also lead to long-term device degradation [215].Diffusion of metal atoms into the Sb2S3 absorber under operational conditions has been reported to deteriorate device performance [216].The selection of stable and chemically compatible contact materials remains a critical challenge [217].Organic hole transport materials often suffer from poor thermal and environmental stability [218].Replacing organic components with robust inorganic alternatives is therefore a key research priority [219].

6.3 Scalability and Manufacturing Constraints

While high-quality Sb2S3 films have been demonstrated at the laboratory scale, translating these results to large-area devices presents additional challenges [220].Solution-based deposition techniques often exhibit poor thickness uniformity and reproducibility over large substrates [221].Vapor-phase techniques, although capable of producing high-quality films, involve higher capital and operational costs [222].Balancing film quality with scalable, cost-effective manufacturing processes remains unresolved [223].Process integration with existing photovoltaic manufacturing infrastructure also poses challenges [224].Compatibility with roll-to-roll processing and flexible substrates requires further optimization of deposition conditions [225].Developing scalable deposition methods without compromising film quality is essential for commercialization [226].

6.4 Future Research Directions

Future research on Sb2S3 solar cells should prioritize comprehensive defect control strategies at both bulk and interface levels [227].Advanced characterization techniques, such as deep-level transient spectroscopy and time-resolved photoluminescence, are needed to identify dominant recombination pathways [228].Combining experimental studies with first-principles modeling can provide deeper insights into defect formation and passivation mechanisms [229].Orientation-controlled growth of Sb2S3 thin films represents a promising pathway to enhance charge transport [230].Techniques that promote vertical alignment of ribbon chains are expected to significantly improve carrier extraction efficiency [231].Interface engineering using ultra-thin passivation layers and graded band structures should be further explored [232].Alloying and compositional engineering offer additional opportunities to optimize bandgap and electronic properties [233].Controlled incorporation of selenium or other chalcogen elements may enable improved carrier transport and reduced recombination [234].Exploration of tandem device architectures incorporating Sb2S3 as a wide-bandgap absorber could unlock higher overall efficiencies [235].

6.5 Commercialization Prospects

Sb2S3 possesses several intrinsic advantages that make it attractive for commercial photovoltaic applications [236].The material is composed of earth-abundant and non-toxic elements, ensuring long-term sustainability [237].Its high absorption coefficient allows for ultrathin absorber layers, reducing material consumption [238].Furthermore, Sb2S3 exhibits superior environmental stability compared to many emerging absorber materials [239].However, closing the efficiency gap with established thin-film technologies remains essential for market competitiveness [240].Continued improvements in efficiency, stability, and scalability will determine the future commercial success of Sb2S3 solar cells [241].With sustained research efforts and technological innovation, Sb2S3 holds strong potential as a next-generation photovoltaic absorber [242].

7. Conclusion

Antimony sulfide (Sb2S3) has emerged as a highly promising absorber material for next-generation thin-film photovoltaic applications due to its earth-abundant composition, low toxicity, and favorable optoelectronic properties [243].The orthorhombic crystal structure composed of quasi-one-dimensional (Sb₄S₆)ₙ ribbon chains impart strong anisotropy to charge transport, which fundamentally governs device performance [244].Its suitable bandgap in the visible range and exceptionally high optical absorption coefficient enables efficient light harvesting using ultrathin absorber layers [245].This review has comprehensively analyzed the structure–property–performance relationships of Sb2S3 thin films, emphasizing the critical role of deposition techniques, crystal orientation, and defect chemistry [246].Both solution-based and vapor-phase deposition methods have demonstrated the capability to produce functional Sb2S3 absorber layers, though trade-offs between scalability, cost, and film quality remain [247].Advances in deposition control, post-treatment processes, and annealing strategies have significantly improved crystallinity and reduced defect densities [248].Considerable progress has been achieved in Sb2S3-based solar cell architectures through interface engineering, buffer layer optimization, and selective contact design [249].Defect passivation strategies, including sulfur-rich treatments and compositional engineering, have proven effective in suppressing non-radiative recombination losses [250].Doping and alloying approaches, particularly the formation of Sb₂(S,Se)₃ solid solutions, offer promising pathways for bandgap tuning and enhanced carrier transport [251].Despite these advancements, Sb2S3 solar cells continue to exhibit a notable efficiency gap compared to their theoretical limits [252].This gap is primarily attributed to residual bulk and interfacial defects, sub-optimal band alignment, and anisotropy-induced transport limitations [253].Addressing these challenges requires precise control over crystal growth orientation, advanced defect characterization, and rational interface design [254].Looking forward, future research should focus on orientation-controlled thin-film growth, atomic-scale interface passivation, and integration of robust inorganic charge transport layers [255].The exploration of tandem and hybrid photovoltaic architectures incorporating Sb2S3 as a wide-bandgap absorber represents a particularly promising direction [256].With continued interdisciplinary efforts combining materials science, device physics, and scalablemanufacturing, Sb2S3 holds strong potential to evolve into a commercially viable photovoltaic technology [257].

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Dr. Dhananjay Pralhad Patil

Vidya Vikas Mandal’s S. G. Patil Arts, Science &     Commerce College, Sakri, Dhule (MS)

Email: dhananjaypatil983@gmail.com

Abstract:

The grief and suffering of those who have been downtrodden and who have become brutal victims of caste prejudice have been captured in works of writing known as downtrodden literature. It is also a potent vehicle for uprising and opposition to untouchability. Instilling a strong resolve to transform society by seizing these marginalized people’s hopes and aspirations, the exploitation of Downtrodden in all spheres of life gives them a strong motivation to do so. Through the analysis of Sharankumar Limbale’s well-known life story The Outcaste, this essay aims to illustrate the picture of suffering and resistance of the oppressed. This essay will also help readers to understand how a Dalit autobiography has developed into a crucial tool for expressing oneself and reclaiming a suppressed sense of selfhood in order to get over the inferiority complex associated with “being a Scheduled Caste.” Through the telling of their stories, downtrodden authors hope to forge a new sense of cultural identity and belonging as well as a place all their own. This literature also demonstrates Sharankumar’s autobiography, “The Outcaste,” as a historical and social narrative that illustrates caste prejudice in society, the deceit of higher caste Hindus, devastating poverty, downtrodden women’s exploitation, and the search for identity.

Keywords:  Caste, Gender, Identity and Marginalization

Introduction:

India has advanced greatly in all spheres of life, but the caste system has persisted there for centuries despite this progress. Despite the fact that oppressed people have existed for generations, they continue to face hostility and are even forbidden from being near Hindus from higher castes. The oppressed are taken advantage of, butchered, kicked, raped, slain, denied minimum pay, and thought to be cursed. Gurram Jashuva accurately captures the plight of the oppressed in Indian culture in his poem “Gabbilam,” in which he expresses his outrage at the crimes committed against the untouchables. According to him, an owl is thought to bring bad luck. However, a downtrodden is not allowed entry inside a temple, while a stray dog can.        

The caste system, which is based on birth rather than ability in India, is totally to blame for the formation of the oppressed in this social arena. The Rigveda’s Purusukta, which explicitly mentions the caste system, is where the word “Dalit” originates. Hindu legend holds that Lord Brahma gave birth to the Brahmans from his mouth, the Kshatriyas from his shoulders, the Vaishyas from his thighs, and the Sudras from his feet. Therefore, Sudras are viewed as the lowest caste—a group of oppressed and marginalized people—while Brahmans are seen as the superior caste. Even Muslims and Christians in India could not avoid the effects of the caste system.

The Marathi dictionary defines the term “Dalit” as having a number of meanings. They are crushed, reduced to pieces, ground, etc. Different regions of India insult Dalits by calling them names like Dasa, Raksasa, Asura, Avarna, Chandala, and etc. The term “untouchable” for members of the lower caste was created by Dr. Babasaheb Ambedkar,. Hindus were referred as the dejected class by the British in 1909. In 1933–1934, Mahatma Gandhi gave them the new name “Harijan”means a child of God, whereas Rabindranath Tagore suggested Hindu upper caste people to call untouchable as an outcaste people. Dr. Babasaheb Ambedkar has given the term Scheduled caste to suppressed downtrodden (untouchable) in our constitution Therefore, entire underprivileged population has been referred as “Scheduled caste” since India became a republic. The oppressed majority often rebels against the rulers’ oppression. Similar to black literature, dalit writings emerged as a protest genre to call attention to all manners of inhumanity. To realize their ambitions and aspirations, to instill a new cultural and social consciousness, to overcome the treatment, humiliation, and caste prejudices in society, to create their own distinct identity.

With Mahatma Phule’s thought, Dr. Babasaheb Ambedkar called for a political movement to bring about balance and offered the untouchables all the rights they had been denied for so long. Writing is a powerful tool for protesting against all types of repression and tyranny. Veteran non-Dalit writers like Rabindranath Tagore, Sarat Chandra Chatterjee, Taru Dutt, Daya Pawar, and others grasp their pens with an egalitarian attitude to speak out against injustice within the servile caste and to raise societal consciousness. Many Dalit authors have written autobiographies to express their traumatic experiences of being oppressed as well as their damaged psyches, including Bama, Sharmila Rege, Narengra Kumar, Jagadhar, Namade Dhanshal, and Sharankumar Limbale. of the Dalit community. Sharankumar Limbale is a writer, editor, critic, Dalit activist, and the creator of 24 books. The essence of Dalit literature is shaped by the life story he tells in his groundbreaking work “Akkarmashi,” which was first published in Marathi in 1984.

In 2003, Santosh Bhoomkar translated his autobiography into English as “The Outcaste.” The fundamental theme of Sharankumar’s work is to establish his mother’s innocence, and he has expertly depicted the misery of his workplace’s irresponsibility. Sharankumar brings up a number of serious points in this book about the caste system and what it means to be a Dalit, but most of his concerns go unanswered.  

Sharankamar Limbale demonstrates in his memoirs how caste prejudice and the associated social stigmatization follow the oppressed everywhere. For them, the moniker “Dalit” turns into a curse. An oppressed person is unable to mingle with Hindu upper castes or move about freely. Sharankumar introduces his readers to the Wani and Brahmin students from the upper castes who used to play their sports apart from the untouchables. The boys from Mahar and Mang have their own games they play among themselves. Caste distinctions were made in the school’s seating layout. The Brahmin and Wani pupils had the front row to themselves in the temple. Seats were set aside lower down in the temple hall for the students from the cobbler community. Hindus from the castes have compassion for the downtrodden  students.

In addition to receiving an education, the downtrodden were assigned the task of collecting dung to cover the walls and floors. The irony is that while the upper castes avoided all contact with the oppressed, they continued to sit on the “baseborn soiled “‘ floor. A disadvantaged person was not allowed within the temple, and there were separate water reservoirs for the various communities. The privilege of using the upstream river to wash their clothes and fill their water containers was reserved for the upper caste. For residential use, the downtrodden gathered water from the river downstream. In the same reservoir, they also used to wash their animals, their clothes, and themselves.

“We are the garbage the village throws out. There were so many caste factions in our school. The umbilical cord between our locality and the village had snapped, as if the village, torn asunder, had thrown us out of it. We had grown up like aliens since our infancy. This sense of alienation increased over the years and to this day my awful childhood haunts me.”(05)

The above cited words suggest the smearing of the hall with dung paste, lighting of the village street lamps, sweeping of the village street, skinning of dead animals, and selling of dead skin are all low-level chores given to untouchables by higher authorities. The upper Caste Hindus in the community pay the Mahar a set amount of grain to carry the dead animal away after it dies. Even while it may seem ironic, it is true that the very animal these people love (in this case, a cow), they detest even touching it after it has passed away.

A person who is oppressed in all facets of life is freed by the caste system. Even the village barber who trims the buffaloes won’t shave a downtrodden head. To get his head shaved, a downtrodden must make a difficult decision. The strap of a Mahar cannot be fixed by the cobblers. The downtrodden have their own sets of cups and saucers that are stored in a tea shop. Latur is a large city in the state of Maharashtra with tall buildings and bungalows, but not a single room is available for rent to a Mahar or a Muslim. The idea of untouchability in Hindu society is contested by Limbale as given below. He says:

“I used clean clothes, bathed every day and washed myself clean with soap, and brushed my teeth with toothpaste. There was nothing unclean about me. Then in what sense was I untouchable? A high caste who is dirty was still considered touchable! This city was made of herds of castes. Even localities were identified by castes.”(107)

As per Limbale, caste prejudice and poverty coexist in a struggling household. Here, Sharankumar Limbale also illustrates two different types of hunger: the need for food and the want for passion. A dejected person typically has to choose between going without food and becoming underfed. A downtrodden is supposedly destined to starve, according to popular belief.

In his child hood Limbale could not control his appetite, so his grandmother ‘Santamai’ would go to the village to ask for some “bhakaris.” His sisters never complained about being hungry, and they go to bed without eating anything. Thus, poor downtrodden were compelled to steal food to fill “the cave of hunger” because they were starving; even they were subject to physical punishment if they caught stealing the food. Consequently, the following quote from Limbale about this topic perfectly sums up his outburst in following  given words, he says:

“Black-marketeers become leaders, whereas those who are driven to steal by hunger are considered criminals.” (Limbale, 21)

The upper castes provided leftover food for the downtrodden. Leftover food is like nectar to downtrodeen. (03) Sharankumar related the story of a school picnic where the Hindus were eating a wide range of dishes while the downtrodden were able to eat only a few dry “bhakaris.” Later, when the caste Hindus’ leftover food was distributed to the Mahar youngsters, they dove in like ravenous vultures. Due of starvation, they consumed rotting, old, and filthy food. Limbale’s grandmother created “bhakaris” out of the grains she salvaged from the animal excrement. These “bhakaris” were difficult to swallow and had an offensive manure odour. The stomach makes you clean crap, and it even makes you eat shit, Limbale declares with justification. (08)

Anyone would be moved to tears by the dreadful poverty in a depressed household. Absolute poverty forced Sharankumar’s family into the vile alcohol industry. Sharankumar and his grandparents used to reside under the bus stand’s squalid surroundings because the bus ridership was their only source of income. The way a prostitute waits for her clients is how they awaited the bus. Under the bus stand’s tin roof, they passed their days and nights. The difficulties they frequently encountered during the wet season are depicted by Sharankumar as given below the words. He claims:

“The village bus stand had large windows, the front almost open. Its roof was made of tin. The rain dripped in through the holes in the roof and drenched us. The chill wind made us shiver. The rain dripped on us throughout the night. Thunder roared and lightening flashed through the wet village…The water becomes streams. In the morning we saw water all over, our village looked as if it had had a bath. Whenever it rained I slept under the bench. Santamai sat shivering in a corner, wrapped in rags. She suffered from rigors. She felt something churn in her stomach.” (Limbale, 51)

Sharankumar Limbale suffers from two social disadvantages as a result of his identity: first, he was born into the Mahar community, and second, he was born out of wedlock. His second identity as an illegitimate kid isolates him from his own community while his Dalit identification distances him from the top classes of society. He is mistreated as a result of being a “keeper’s” child. He considers it inconvenient to enroll oneself in the

school. His illegitimate status prevented him from marrying the woman he loved. He eventually succeeds in marrying a girl, but only after great difficulty. A child inherits both the surname and the identity of his father in a patriarchal society like that of India and the subcontinent. However,  an unborn kid. He stated in given line:

“Why did my mother say yes to the rape which brought me into the world? Why did she put up with the fruit of this illegitimate intercourse for nine months and nine days and allow me to grow in the foetus? Why did she allow this bitter embryo to grow? How many eyes must have humiliated her because they considered her a whore? Did anyone distribute sweets to celebrate my birth? Did anyone admire me affectionately? Did anyone celebrate my naming ceremony? Which family would claim me as its descendant? Whose son am I, really?” (37)

The persona of Sharankumar Limabale is complicated. He criticizes the high caste individuals who cower at the least touch of the oppressed but continue to prey on Dalit women to sate their lustful appetites. Additionally, because of the “unbridgeable divide” between the father and the son, the child born from such an unlawful relationship is denied paternal affection and affiliation. For a parent to give his son his name and standing in this culture, his honor would be on the line.

 “My father lives in a mansion, my mother in a shack, and I on the street,” he says, feeling mentally agitated by his sense of estrangement and rootlessness. Where shall I perish? “Exactly where are my roots?” (62)

Limbale was only 25 years old when he penned this novel. His desire for Identity is stronger when he is younger. He forges a bond with Karna, the fabled son of Kunti. He understands that in this society, a guy can only be identified by his caste, religion, or parent.

He doesn’t really belong anywhere because he lacks both of them. Because his father was from another village, Balsegaon, other boys in Maharwada used to call him “akkarmashi,” which meaning an orphan or a pariah, and he was expelled from the community hall. He could only manage to have the identify of a “akkarmashi” (an unclean or an illegitimate child).

 Sharankumar portrays his grandmother, Santamai, as an elderly woman whose skin ages and becomes dry from exposure to the sun on a regular basis. Her teeth become darker as a result of the usage of herbal powder, and Santamai, who was perspiring, had a blacksmith’s appearance in the light of the stove’s fire. (11)

In their autobiographies, numerous oppressed women writers have expressed their deep emotions in literature. In his memoirs, Sharankumar Limbale conveys his sincere compassion for oppressed women. He also discusses how oppressed women are victimized and marginalized, citing his grandmother and mother as two egregious examples. His Masamai and Santamai are independent women who work outside the home to support themselves. Santamai gets up early in the morning to sweep the village street. And Masamai establishes a home-based liquor business and serves alcohol to the clients.

It’s a curse to be gorgeous in a community of Scheduled Cast people. The high caste Patils has a tradition of creating whores from the Dalit population and having children out of wedlock with oppressed women. He has been forced to choose between the lust and hunger games, and His Masamai is a victim of such persecution. Her home is destroyed by a Patil named Hanmanta Limbale, who also takes her away from her adoring husband and nursing children and keeps her as a “keep” in order to satiate his lust. Later, he abandons her after she gives birth to a child.

She later becomes the concubine of Yeshwantrao Sidramappa, a different Patil from a different village, with whom she had eight children not through marriage. Masamai degrades herself from the status of a wife to that of a whore after getting divorced in order to have a family and provide for them, as a divorced downtrodden

Woman is not permitted to remarry but her divorced husband is permitted to do so numerous times. Limbale very skillfully explains this gender politics in the lines that follow:

“A man can eat paan and spit as many times as he likes, but the same is not possible for a woman. It is considered wrong if a woman does that. Once her chastity is lost it can never be restored.” (36)

Hindus from the upper castes sexually objectify the body of oppressed women. In his writing, Limbale exposes the corruption and hypocrisy of the so-called high caste population as well as the lustful wrongdoings committed by landowners and clergy under the guise of caste and religion. Even to the point of offering his wife to the gloomy darkness of the Patil mansions, a downtrodden man will go. A few Dalit communities have a custom of dedicating a girl child to the gods. These young women spend a significant portion of their lives engaging in ritualistic worship. These women are referred to as “devadasis” (a dancer-prostitute dedicated to the deity and the patrons of a temple). The priest and the kids later have them inked on their thighs.

The downtrodden women frequently experience “rape,” whether the women are victimized by high caste landowners or by their own males. Sharankumar cites the case of Dhanavva, a destitute widow whose father raped her on purpose after her husband’s passing. This arrogant man proudly admits his deed rather than feeling any remorse:

“I have sown the seed from which she has grown as a plant.” Now why shouldn’t I eat the fruits of this plant? (67)

Black people experience the same cruel torture that Toni Morrison depicts in her well-known book “The Bluest Eye,” in which Pecola is sexually assaulted by her own father:

“We had dropped our seeds in our own little plot of black dirt just as Pecola’s father had dropped his seeds in his own plot of black dirt. Our innocence and faith were no more productive than his lust or despair” (5).

Conclusion

As per the above cited words of Author it concludes that the main goal of downtrodden literature is to raise social consciousness among the underprivileged in order to spark a revolution. In fact, Sharankumar Limbale’s autobiography serves as an outlet for his suppressed opposition to the caste system. He paints a negative image of caste prejudice in this book, including its impact on poverty, the search for identity, and the misery of oppressed women. In the same way that black literature addresses the agony and suffering of the Negros, Downtrodden writing carves out a distinct niche for itself by examining the issues and struggles of the oppressed people in their own native tongues.

Sharankumar is a symbol of the community’s overall resilience, which overcomes challenges head-on and emerges with grace at each step. His autobiography’s release has enabled him to successfully revolt against the debased Hindu establishment and its persistent caste stereotypes as well as to forge a depressed sense of self. The autobiography of Sharankumar Limbale is not just an honest account of a single person; it also serves as a narrative about the past and contemporary conditions of the underprivileged community. Consequently, Sharankumar Limbale’s autobiography is a burning explanation as well as a potent representation of an impoverished community in the modern setting.

Works Cited:

Bhaskar, Talluri Mathew. “Shrankumar Limbale’s The Outcaste (Akkarmashi): A Dalit Perspective.” Scholar Critic, vol.1,no. 3, December 2014. Accessed 15 February 2017.

Jamdhade, Dipak Shivaji. “The Subaltern Writing in India: An Overview of Dalit Literature.”The Criterion- An International Journal in English, vol 5, no.3, June 2014.Accessed 30 December2016.

Limbale, Sharankumar. The Outcaste: Akkarmashi. Translated by Santosh Bhoomkar, New Delhi: Oxford University Press, 2008.Print.

Morrison, Toni. The Bluest Eye, London: Vintage Books, 1999.Print.

Ramanathan. S. “Situating Dalit Literature in Indian Writing in English.” Language in India, vol. 14, no.12, December 2014. Accessed 21 January 2017.

Thomas, Ashly. “Interrogating Casteism: An Althusserian Reading of Sharankumar Limbale’s Akkarmashi The Outcaste.”Galaxy: International Multidisciplinary Research Journal, vol.7, no. 2. April 2016. Accessed 2 March 2017.

Nagarale, D. V., Khairnar, B. J., & Girase, P. S. (2026). Antimicrobial Investigation of Knoevenagel Products of Quinoline Derivatives. International Journal of Research, 13(13), 68–73. https://doi.org/10.26643/ijr/2026/s13/7

¹Deepak Vasant Nagarale, ²Bhikan J. Khairnar, ³Pravinsing S. Girase*

¹*Department of Chemistry, VVM’s S. G. Patil College, Sakri, Dhule

²S. S. V. P. S’s. L. K. Dr. P. R. Ghogrey Science College, Dhule

³M. D. Sisode College, Nardhana

Corresponding Authors Email: deepaknagarale03@gmail.com

Abstract:

We have described anti-microbial screening of synthesized compounds. All these compounds screened giant’s standard antibacterial and antifungal agents. The detail of biological activity of these active compounds were discussed and results are moderate to high the zone of inhibition obtained.

Kay Words: Antibacterial, Antifungal agents, dicarbaldehydes, Microorganism.

Introduction:-

Involvement in biological procedures makes particular molecular unit uniquely important and interesting [1]. However, the very importance of biological processes has fostered piecemeal approaches to the description of functional relationships between biological activities and the chemical substances that express them. The biological activity of a organic compound is given by A=cf, where A is the activity, c is the concentration of substance and f is a parameter designated as ‘‘inherent activity.’’ The type of activity, catalytic (katal) or binding (mol-1 L) determines units and dimensions[2].Biological activity provides both biologically information and that enables development of the quantitative dimensions needed to exploit the new knowledge [3].

8.2 Biological Activities:-

In this paper we have described anti-microbial screening of synthesized compounds. All these compounds screened giants standard antibacterial and antifungal agents. The detail of biological activity of these active compounds were discussed and the results are given in TablesThe evaluation done for various derivatives for antibacterial activity and literature procedure shows agar diffusion method by finding the zone of inhibition of the drug sample against the standard drugs.

Procedure-I: Stock solutions of test compounds and standard drug:-

Compounds were taken as test samples along with a standard drug samples. 10 mg of each test compound dissolved in 1 ml of DMSO for preparing stock solution of standard drugs.

Organisms used for experiment:-

 The organisms employed in the in vitro testing of the compounds were Staphylococcus aureus (Gram positive), Bacillus subtilies (Gram positive), Pseudomonas aeruginosa (gram negative), Escherichia coli (gram-negative) bacterias and Candida albicans (gram-negative) fungi. All the cultures maintained on nutrient agar (Microbiology grade, Hi Media) medium by periodic sub culturing.

Preparation of inoculum:

Procedure for the preparation of inoculums for all the organisms was same. The inoculum was prepared within 24 hrs. From old growth of organism on nutrient agar slant with the help of sterile nichrome wire loop. The growth of the organism on slant especially transferred to a tube containing sterile distilled water.

Medium:

Nutrient agar (1.5 g, Microbiology grade, Hi Media) dissolved in sterile distilled water (100 ml) and Poloxomer 182 (3 g)added as a surfactant to the media to prevent the drug precipitation. 20 ml of this stock solution taken to each Petri dish.

Test Mechanism:-

Petri dish containing approximately 20 ml of disinfected nutrient agar, 0.1 ml of reliable culture of test organisms spread. The stock solution added from four bore wells having 5-20 µl[4,5].This matches to concentration range of 30 µg/ml of the test compound. The tests carried out in duplicate. To one side from placing the controls of standard drug (Ciprofloxacin), controls with dimethyl sulphoxide (Positive control) and without dimethyl sulphoxide (Negative control) were also contained within in the test[6].

Incubation:-

Incubation period for microorganism growth was 37°C for 24 hours under dark conditions. Zone of inhibition were determined at the end of incubation period [7].

8.3 Results and Discussion:-

Section-I: Antimicrobial Study of Knoevenagel Products of Quinoline:-

We have synthesized biologically active Knoevenagel products of 2-chloro-3-formyl quinolines with active methylene compounds, which shown in Tableand results of their microbial screening shown in table.

Table 1: Synthesized Knoevenagel Products of Quinoline

3a-r 3a-r	Sr. No.	Compound No.	R-
		3a	-H
		3b	-H
		3c	-H
		3d	-H
		3e	-H
		3f	6-Cl, 8-NO2
		3g	6-Cl, 8-NO2
		3h	6-Me
		3i	6-Me
		3j	6-Me
		3k	6-Cl
		3l	6-Cl
		3m	6-Cl
		3n	7-OMe
		3o	7-OMe
		3p	7-OMe
		3q	7-OMe
		3r	7-OMe

Table 2: Antimicrobial Screening of Knoevenagel Products of Quinoline

Compound No.	Inhibition Zone Diameter (mm)
	Sample code	S.aureus	B.subtilis	P. aureginosa	E. coli	C. albicans
3a	Pm33	–	–	–	–	8.24
3b	Pm34	7.34	7.12	–	–	7.53
3c	Pm35	–	–	–	–	–
3d	Pm36	–	–	–	–	–
3e	Pm37	–	–	–	–	–
3f	Pm38	10.26	10.58	–	–	11.28
3g	Pm39	–	–	–	–	10.60
3h	Pm40	–	–	–	–	6.90
3i	Pm41	–	–	–	–	7.10
3j	Pm42	–	–	–	–	–
3k	Pm43	–	–	–	–	9.27
3l	Pm44	–	–	–	–	8.96
3m	Pm46	–	–	–	–	–
3n	Pm47	–	–	–	–	–
3o	Pm48	–	–	–	–	–
3p	Pm49	–	–	–	–	–
3q	Pm50	–	–	–	–	–
3r	Pm51	–	–	–	–	–
Chloramphenicol	–	24.58	24.55	25.22	25.44	–
Amphotericin B	–	–	–	–	–	12.58
“ – ” Zone of Inhibition

Figure 1: Line graph of Antimicrobial Screening of Knoevenagel Products of Quinoline

Antibacterial Study:-

Compounds 3b, 3f showed moderate activity against S. aureus, and B.subtilisr respectively when compared to the standard drug Chloramphenicol at tested concentration.

Antifungal Study:-

 Among the screened compounds 3f, 3g showed significant and 3a,3b, 3h, 3i, 3k and 3l showed moderate activity against C. albicans when compared to the standard drug Amphotericin B at tested concentration.

Conclusion:-

We conclude the overall observation about some of the synthesized compounds. Compounds were showed antimicrobial activity, with compared to standard drugs. Compounds 3b, 3f,5a, 5b, 5d, 5e have showed moderate anti Bacterial activity and compounds 3f, 3g, 5b and 5d have showed superior antifungal activity, while 3a, 3b, 3h, 3i, 3k, 3l, 5c, 5e  have showed  moderate antifungal activity.

References:-

1. World Health Organization(2000) ,WHO consultation on international biological standards for in vitro diagnostic procedures. WHO, September (2000), Geneva, Switzerland.
2. C. M. Jackson, M. P.Esnouf, D. J. Winzor, D.L. Duewer, A.Q.Assur,  12(2007), 283.
3. J. Wyman., J.M.Biol., 11(1965), 631.
4. G.A.Pankey and L.D.Sabath.,Clin. Infect, Dis, 38(2004),  864.
5. A. E.Zoerby, F.Sanschagrin,R. C. Levesque.,Mol. Microbiology, 47(1) (2003),1.
6.  W.Foye. Principles of Medicinal Chemistry (IV^thEdn.), WAVERLY,821.
7. T. W. Chu Daniel, J. J. Plattner., J. Med. Chem, 39(20),(1996), 3853.

Citation

Wagh, B. S., & Tambe, S. S. (2026). Traditional Uses and Conservation Status of Ceropegia Species in Satana Tehsil of the Northern Western Ghats. International Journal of Research, 13(13), 56–62. https://doi.org/10.26643/ijr/2026/s13/5

Bhushan S. Wagh¹, Satish S. Tambe²

Department of Botany, L.V.H. Arts, Science & Commerce College, Panchavati, Nashik.

Bhushan49wagh@gmail.com (corresponding author)

Abstract

India has a diverse basin of flowering and medicinal plants with four biodiversity hotspots. The use of plants as medicine was traced to the Vedic period. From ancient times,the value of Plants shows an enormous ability to tackle diseases. Humans are dependent on medicinal plants for various purposes, such as medicines,cosmetics,and other resources. In modern days, tribal communities like Kokana, Bhilla, Koli, and others are completely reliant on medicinal plants to fulfill theirdaily needs.

Ceropegia L. belongs to the family Asclepiadaceae, native to Africa, Southern Asia, and Australia. It is a botanically curious genus, mainly distributed in the Western Ghats. The genus comprises 200 species found throughout the world, mainly distributed in subtropical and tropical Asia. In India, 55 species are reported, of which 28 are endemic to Peninsular India.A total of 6 species and 2 varieties of this genus have been recorded in the Nashik district.The pharmacological importance of the genus is mainly due to the presence of ‘cerpegin’, a pyridine alkaloid, apart from the different potential phytoconstituents such as steroids, terpenoids, anthocyanins, anthracene glycosides, coumarins, flavonoids, fatty acids, phenolic compounds, alkaloids, and carotenoids.The given study explores the important ethnobotanical uses of the genus Ceropegia.

Keywords– Ceropegia L., Asclepiadaceae,Ethnobotany, Medicinal plants, Western Ghats

Introduction–

The occurrence of Ceropegia is very restricted to a narrow range of habitats. As they prefer to grow in moist, shady, and isolated regions.Ceropegia L., with more than 200 species, is distributed in tropical and subtropical regions of the world. Maximum diversity of Ceropegia occurs in southeastern Asia, India, Madagascar, tropical Arabia, South Africa, and Kenya (Meve 2002). The genus is represented by 53 species, two subspecies, and six varieties in India, of which 41 taxa are endemic to India. A majority of the species are under threat as per Kambale & Yadav (2019).The hilly region of Satana tehsil is one of the natural hubs for threatened plant species.Villages likeSalher, Mulher, Bhilwada, Antapur, etc has great diversity of medicinally important plants.  Most species of Ceropegia were categorized as endangered in the Red Data Book of Indian plants.(The Indian Plant Red Data Book-I, 1984.)As per(Wagh, Tambe, 2025.)the ceropegias like to grow at high altitude, about 926m.

Despite the rich ethnobotanical knowledge in the Satana tehsil, Ceropegia species are still very poorly studied, especially regarding their local uses and indigenous knowledge. These plants are known to have pharmacological importance due to the presence of alkaloid compounds such as cerpegin and other ingredients, including flavonoids, terpenoids, and anthocyanins (Nikam et al., 2018). So, studying how local communities in Satana tehsil identify, collect, and use Ceropegia plants in traditional medicine is both important and timely. Many Ceropegia species found in the Western Ghats and Nashik district are reported to be threatened or endangered due to habitat loss, grazing, and human activities, which highlights the need to document traditional plant knowledge for conservation and sustainable use (Sangale et al., 2024).

This study will be helpful to documenting the uses of Ceropegia and local medicinal knowledge to understand its importance and need for conservation.

Methodology–

In the present ethnobotanical study on the genus Ceropegia, carried out in Satana tehsil, Nashik district, Maharashtra. The study area includes hilly regions, forests, and tribal villages where Ceropegia species are naturally distributed. Fieldwork was conducted during the monsoon season of 2025 to record maximum plant diversity and traditional ethnobotanical knowledge.

Ethnobotanical information was collected through regular field visits and interaction with local tribal communities. Informants included elderly villagersknown for their knowledge of medicinal plants. Interviews questionary was used to collect information simply. Details such as the local name of the plant, plant parts used, method of preparation, mode of administration, and traditional uses were carefully noted.

Regular field visits were conducted with knowledgeable informants to locate Ceropegia plants in their natural habitats. During these explorations, plants were observed and photographed. The collected ethnobotanical data were organized and analyzed to understand the importance of different Ceropegia species in local healthcare practices. The methodology followed standard ethnobotanical guidelines to ensure authenticity and reliability of the recorded information (Jain, 1995; Martin, 2004).

Resultand Discussion –

Plant Name	Local Name	Plant Part Used	Traditional Use	Medicinal Properties
Ceropegia bulbosa Roxb.	Kadu khardi	Tuber, leaves	Consumed for diarrhea, dysentery, and kidney stones; used as a tonic	Digestive, anti-urolithic, antioxidant
Ceropegia lushii Graham	Kadu khardi	Tuber	Eaten raw/cooked to relieve stomach pain and weakness	Nutritive, cooling, digestive
Ceropegia vincaefolia Hook.	Dudhi khardi	Tuber	Used as food during scarcity; treatment of gastric troubles	Energy-giving, stomachic
Ceropegia mahabalei Hemadri	Madhu khardi	Tuber	Consumed for general health and vitality, increases fertility in women.	Tonic, nutritive
Ceropegia hirsuta Wight &Arn.	Madhu khardi	Tuber	Used for indigestion and body weakness	Digestive, restorative

The present ethnobotanical study carried out in Satana tehsil of the northern Western Ghats of Maharashtra highlights the rich traditional knowledge associated with selected species of the genus Ceropegia. Interactions with tribal and rural communities revealed that Ceropegia bulbosa, C. lushii, C. vincaefolia, C. mahabalei, and C. hirsuta are mainly valued for their underground tubers, which are used both as food and medicine. Among these, Ceropegia bulbosa was found to be the most frequently used species. Its tubers are commonly consumed to treat digestive problems, diarrhea, dysentery, and urinary ailments such as kidney stones, and are also considered a general health tonic. Other species, particularly C. lushii and C. vincaefolia, are eaten raw or cooked to relieve stomach pain, weakness, and dehydration, especially during times of food scarcity. The tubers of C. mahabalei and C. hirsuta are known for their nutritive, cooling, and restorative properties and are therefore used as energy-giving foods by local people (Jagtap & Singh, 1999; Yadav & Sardesai, 2002; Patil, 2013).

The widespread use of tubers across all recorded species shows their importance as survival foods and traditional remedies in the semi-arid and hilly regions of Satana tehsil. However, information shared by local informants also pointed to a noticeable decline in natural populations of these plants. This decline is mainly due to habitat destruction, grazing pressure, forest clearance, and excessive collection of tubers before the plants can produce seeds. Many of the documented species are narrow endemics of the Western Ghats and fall under threatened categories of the IUCN Red List. Ceropegia mahabalei and C. hirsuta are classified as Endangered, while C. lushii and C. vincaefolia are considered Vulnerable because of their limited distribution and decreasing populations. Although C. bulbosa has a comparatively wider distribution, local overexploitation has raised concerns about its future survival (IUCN, 2023).

Ceropegia species play an important role in the traditional healthcare system and food security of tribal communities in Satana tehsil. At the same time, unsustainable use poses a serious threat to their conservation. There is an urgent need to create awareness among local communities, promote in situ conservation, encourage cultivation trials, and adopt community-based management practices. Combining traditional ethnobotanical knowledge with conservation planning can help protect these valuable and endemic plant species of the Western Ghats.

The findings emphasize that while Ceropegia species play a crucial role in traditional healthcare and food security of tribal communities in Satana tehsil, unsustainable use poses a serious threat to their conservation. There is an urgent need for awareness programs, in situ conservation, cultivation trials, and community-based management strategies to ensure sustainable utilization. Integrating ethnobotanical knowledge with conservation planning can help protect these ecologically and medicinally important endemic plants of the Western Ghats.

^{Image 1. Ceropegiahirsuta                                                                         Image 2. Ceropegiavincaefolia}

                   ^{Image 3. Ceropegiamahabalei                                                                     Image 4. Ceropegiabulbosa}

Acknowledgement –

The author wishes to express sincere gratitude to the Principal, L.V.H. Arts, Science & Commerce College, Panchvati, Nashik, for providing the necessary facilities, encouragement, and institutional support to carry out the present ethnobotanical research. Special thanks are extended to the tribal and rural communities of Satana tehsil, Nashik district, for generously sharing their valuable traditional knowledge and cooperation during fieldwork. The support and guidance received from all those who directly or indirectly contributed to this work are gratefully acknowledged.

References –

IUCN. (2023). The IUCN Red List of Threatened Species. International Union for Conservation of Nature.

Jagtap, A. P., & Singh, N. P. (1999). Folk medicinal plants of India. Scientific Publishers, Jodhpur.

Jain, S. K. (1995). A manual of ethnobotany. Scientific Publishers, Jodhpur.

Kambale, S. S., & Yadav, S. R. (2019). Taxonomic revision of Ceropegia (Apocynaceae: Ceropegieae) in India. Rheedea, 29(1), 1–115.

Martin, G. J. (2004). Ethnobotany: A methods manual. Earthscan Publications, London.

Meve, U. (2002). Ceropegia, pp. 63–106. In: Albers, F. & U. Meve (eds.), Illustrated handbook of succulent plants: Asclepiadaceae. Springer, Berlin, 274 pp.

Nikam, T. D., Ebrahimi, M., & Patil, V. A. (2018). Phytochemistry and pharmacological potential of the genus Ceropegia: A review. Journal of Pharmacognosy and Phytochemistry, 7(3), 1234–1242.

Patil, D. A. (2013). Ethnobotany of Maharashtra. Daya Publishing House, New Delhi.

Sangale, et al. (2024). Several Ceropegia species from the Western Ghats are reported to be threatened, highlighting the need for conservation.

The Indian Plant Red Data Book–I. (1984).

Wagh, B. S. (2025). A short note on new distributional record of Ceropegia mahabalei from Dhule District of Maharashtra. https://doi.org/10.11609/ijar.3103

Yadav, S. R., & Sardesai, M. M. (2002). Flora of Kolhapur District. Shivaji University, Kolhapur.

Citation

Raut, B. J. (2026). Manupatra Legal Database and Current Era of an Artificial Intelligence. International Journal of Research, 13(13), 32–49. https://doi.org/10.26643/ijr/2026/s13/3

Bhupendra J. Raut

 Ph.D. Scholar, KBCNMU, Jalgaon

Abstract

AI is being incorporated into legal research databases which will change how legal information is accessed, organised and interpreted significantly.  Manupatra (one of the largest legal research databases in India) lies at an important intersection of traditional forms of accessing legal information and the new generation of advanced AI-enabled legal research tools. This study has been developed in response to the significant increase in the number of judgements, statute material and regulations in India which has made traditional keyword-based systems of legal research increasingly ineffective.  This study will evaluate how AI-enabled features within legal databases are changing legal research practices and may raise important ethical and governance issues as well.

This study will be based on a doctrinal and analytical research methodology based purely on secondary data sources which include scholarly literature about legal technology, artificial intelligence and digital legal research systems. The article provides a comprehensive overview of the progression of legal research from traditional methods to electronic formats and finally to AI-assisted legal research tools such as Manupatra. Furthermore, the article critically appraises the ethical issues associated with using AI for legal research, including algorithmic bias, transparency and data concentration to name just a few. While AI improves the efficiency, contextual understanding and depth of legal research it will potentially standardise legal thinking / reasoning and exacerbate existing inequalities in society if no regulation is implemented.

The author highlights some of the ways that Manupatra’s AI enhanced legal research improves precision and connectivity by using AI, but also recognises that better standards for transparency, ethics and inclusive access are needed to optimise its use in legal research. The author makes a recommendation that AI should only be an assisting tool in legal research not the key determinant in legal reasoning. Lastly, the author states that effective regulation of AI legal databases through governance, oversight and capacity building will assist in ensuring AI legal databases move towards improving fairness, pluralism and access to justice in India.

Keywords: Artificial Intelligence, Legal Research Databases, Manupatra, Access to Justice, Legal Technology

1. INTRODUCTION

In the Indian legal ecosystem, Manupatra has become one of the most well-known digital research platforms that has been created with an objective to alleviate the aspects of scale, complexity, and fragmentation of the vast amount of legal information on India’s courts, statutes, tribunals, regulatory materials, etc. To create a research environment that can support researching large numbers of case laws and legal texts, Manupatra has to create a collection of actionable items that are searchable, can link to other case laws, and are fully supported with structured finding tools such as subject classification and citation links; a critical requirement to a legal system where precedent and cross-references play a significant role in the legal reasoning process. Manupatra’s own available training and product documentation describes it as an online legal research solution that facilitates search and retrieval by providing structured search and retrieval interfaces and back-end mechanisms that help to reduce the time spent searching through large volumes of legal material (Manupatra, n.d.-a; Manupatra, n.d.-b).

In direct contrast, the advent of Artificial Intelligence (AI) has opened a new chapter in the history of legal research. With the use of machine learning and natural language processing systems that allow for the automated interpretation of vast quantities of text, as well as the ability to identify patterns that are not quickly identifiable through traditional keyword searches, AI has changed the way legal scholars approach the task of researching legal issues. Although AI’s application in the field of law has been understood to include a variety of computational techniques aimed at performing legal tasks such as information retrieval, classification, summarization, and prediction, the adoption of these technologies also introduces new concerns about lack of transparency and accountability, and the potential for erroneous results to be introduced into the legal process. A broader understanding of the impact of these technologies is important because it highlights that the purpose of conducting legal research is no longer simply to find relevant documents but rather, to manage the overwhelming amount of information available while still providing the necessary level of interpretative accuracy, procedural fairness and professional integrity (Surden, 2019).

As the quantity of legal resources dramatically outdistances the limit of human ability to read, analyze and compare them, so too does the urgency of the need to study Manupatra in today’s age of AI. Traditional keyword searches are frequently unable to capture critical nuances in the law because many concepts may be articulated in differing ways in separate cases, and the relevance of a legal concept often relies heavily on the context within which it is found (i.e., facts, issues, outcome, and how future courts have interpreted similar decisions). An additional aspect of this issue is that AI can facilitate access to and retrieval of case law through the use of semantic search capabilities, citation analytics, and automated recommendations to direct the user from one useful piece of authority to another in a more efficient manner. An indication of the current evolution of Manupatra includes a specifically created narrative for an AI-centric legal technology suite, which places the overall process of legal research within a broader context of a workflow that is supported by the use of AI in legal operations (Manupatra, n.d.-c; Surden, 2019).

This research is motivated by both practical and normative considerations regarding the accuracy, transparency, accessibility, and ethics of AI-supported legal research – especially when these tools are provided as part of proprietary platforms. If recommendation systems do not have an explainable rationale for why certain cases were ranked higher, there may be no way for users to assess how that ranking may affect their argument and potentially influence the outcome in a courtroom. The risks inherent with using AI-generated outputs become increasingly apparent when used without an adequate validation process – as exemplified by various incidents reported recently whereby legal documents contained non-existent citations that have been incorrectly attributed to an artificial intelligence tool. These examples highlight that while AI tools may enhance overall efficiency, they do not relieve the user from his or her obligation to verify and confirm the accuracy of any work produced (The Guardian, 2025).

This paper explores the research question of how the proprietary legal database Manupatra has been adapting to meet AI expectations while also meeting the requirements of speed and convenience (i.e., to practitioners) and reliability, interpretive neutrality, and access to justice (i.e., to the public). The purpose of this study is to critically evaluate Manupatra’s current role, capabilities, limitations, and direction in the AI-enabled legal research ecosystem. This evaluation considers how AI will change the way lawyers conduct legal research, how professionals will become dependent on technology, and how AI will affect fairness in information access.

In conducting this study, the researchers utilized a doctrinal and analytical approach to research methodology and relied solely on secondary source materials. Sources included, but were not limited to, peer-reviewed open access academic literature on artificial intelligence and law; publicly available legal informatics research studies; policy and institutional documentation about legal technology; and platform documentation that may be freely available. In synthesizing these sources of information across the fields of legal technology, artificial intelligence governance, and digital legal research, the researchers used comparative and thematic analysis to produce structured insights regarding the benefits, risks, and governance requirements that apply to AI-based legal databases.

2. ARTIFICIAL INTELLIGENCE AND THE EVOLUTION OF LEGAL RESEARCH SYSTEMS

Phases of evolution in legal research illustrate how legal information is stored, classified and organised. The earlier manual way of performing legal research involved using printed sources of law: case law reports, digests, citators and treatises. The ability to find and use legal authority was dependent upon the expertise of the researcher in making the application. Although providing an analytic basis for reading with care and doctrinal precision, the earlier manual method for conducting legal research was also fundamentally constrained in three ways: (1) research relied heavily on physical access to libraries; (2) the availability of reports; (3) the ability of lawyers to follow a taxonomy determined by the editorial structure of the relevant publication in order to identify which authority was “relevant” to their research problem. The way legal information is compiled has never been “neutral”. It is through the classification of legal material and the editorial decisions that determine how professionals attend to legal material, and thereby effectively standardise legal understanding, over time (Berring, 1987).

The introduction of full-text databases and computer-aided legal research was a significant technological advancement around legal research. Instead of having to use indexes for finding cases or legal articles, attorneys are able to rapidly perform searches with Boolean and free-text queries across an entire body or corpus of cases. While this change increased access to legal resources and reduced the amount of time required to find those resources, it also impacted research habits. Lawyers increasingly began their research by formulating search strings rather than thinking about the concept before searching and using printed resources like digest using the 3rd edition of Digest of Decisions of the United States Supreme Court to identify the areas they plan to research then, using those digests when researching to identify those cases you are going to use. The early digital tools did not automatically fix the larger question of how to determine meaning in law. Because the determination of meaning or legal reasoning requires contextual, factual, procedural, and subsequent court treatment of each case, keyword searches are often, too broad or too narrow. Thus, while they are able to execute their research at a much faster pace, there is still a significant amount of interpretation required, on the part of the researcher, to convert the results from the digital research into usable authority (Berring, 1986).

AI fundamentally changed legal research from retrieving documents to extracting meaning and discovering relationships. To achieve this, AI-based systems depend largely on natural language processing to interpret text beyond literal keywords and find documents conceptually similar to one another. A semantic search enables systems to identify relevant cases that use different word combinations or phrases to express the same legal idea. Also, citation networks expand the ability of systems to identify relevant cases by graphically representing the precedential relationships between cases (instead of treating cases as discrete documents, systems treat cases as nodes in a graph of influence and treatment of one another), showing clusters of cases, lines of authority and trends in judicial emphasis over time. Recommendation algorithms provide another means of identifying relevant authorities or cases by learning the patterns of usage of various legal materials, then recommending authorities, quotes of a particular passage or doctrinal paths regarding the question or document (Ashley, 2019).

Global advancements of AI-enabled legal research technologies have demonstrated increased efficiency gains and enhanced contextual assistance. The most recognizable benefit has been the reduction of time: AI-enabled systems are able to identify which cases will most likely be relevant for review, identify important passages within a case, and highlight connections between multiple cases that would have otherwise required users to perform multiple searches to verify. This has a particular value in environments that are experiencing rapid growth in litigation activity and expanding decision making capabilities. A second benefit is that AI systems will assist users in thinking about a judgment not only as a single authority, but as part of a larger system of doctrine, where future citations, negative treatments, and “side” reasoning will affect the practical impact of a particular authority. Many users have time limitations; therefore, AI systems can serve as decision-support tools that will limit the amount of time users will spend searching for information and assist them to focus their attention more effectively (Hellyer, 2005).

The features of AI tools that make them useful also introduce new risks. The primary issue of risk is over-reliance on AI systems because ranked results and recommendations can lead to a false sense of completeness, especially if users treat top-ranked outputs as fully valid authorities. In the law, relevance is subjective and dependent on context, arguments, and issue type (e.g., fact pattern) for any given case in any given court. If the logic of the recommendation system is not transparent to the user, they may not know why some authorities are given more prominence than others. It is this lack of transparency in how a case has been analyzed that is most problematic for users because the law requires that lawyers provide justification for their authority choices and reasoning processes, while judges should base their decision on arguments that can be traced back to valid source(s) and/or verify logical basis(es) used by each party. Consequently, ethical discussions around AI tools for use in the practice of law increasingly define them as supports that remain secondary to the verification and accountability established through the professional ethic of practice by lawyers and judges, rather than as alternatives to professional practice (Walters, 2019).

A serious challenge is presented by the possibility that algorithmic systems will reinforce existing paths of judicial authority through their use of citation ranking systems. A citation ranking system may work well for common or accepted doctrines; however, the same system may inadvertently do extensive harm to dissenting voices, to less commonly used doctrines or to newly established doctrines that are not widely cited. Over enough time, this situation creates a scenario such that a researcher seeking out an opinion has his or her results influenced by where the system directs him/her to look, rather than by where the most analytically appropriate source may be found for the specific issue being addressed by the researcher. In practical terms, the researcher will be limited by what the prevailing system directs him or her to consider and as such will develop procedural patterns consistent with “recommendation” based systems rather than those consistent with an exploratory thought process. This issue is not merely a technical one; this also presents a methodology problem in terms of the way legal reasoning will be conducted and the way in which the ability to think outside the box will develop (Ashley, 2019).

AI is not just about speedy searching; it also denotes an alteration in how we conduct our research as it changes the first thing that Legal Professionals do when engaging with a Legal Text, the primary focus of their search, and what constitutes ‘authoritative’ sources. Also, AI will change how we interact with Legal Texts in that we now will have an added layer of Computational Interpretation that translates from User to Source Material. Therefore, while AI can decrease workloads and enhance accuracies, it will also create a greater need for Critical Oversight, Transparency Norms, and Professional Discipline in order to evaluate the credibility of the source, challenge the validity of Ranking Systems, and ensure you consider as many different Research Fields as possible when conducting Research (Walters, 2019; Hellyer, 2005).

Table 1: Evolution of Legal Research Systems

Phase	Research Method	Core Characteristics	Key Limitations
Manual Era	Printed law reports, digests, citators	Deep doctrinal reading; human interpretation; editorial classification	Time-intensive; physically constrained access; taxonomy dependence
Digital Database	Full-text databases; Boolean/keyword search	Faster retrieval; broader coverage; searchable corpora	Contextual gaps; search imprecision; heavy reliance on query formulation
AI-driven Era	NLP, semantic search, citation networks, recommendations	Context-aware retrieval; relationship mapping; interpretative assistance	Opacity; interpretative dependence; potential reinforcement of dominant trends

The AI systems significantly improved time and the contextual relevance of information and increased transparency and reliance on interpretations by providing clear evidence of the methods and rankings used to generate algorithm-generated output; therefore, requiring critical evaluation and monitoring (oversight) because the manner in which these algorithm-generated recommendations influence legal reasoning and the selection of authority is often unclear. Through the transformation of legal research from one of gathering information to one of assisting in interpretation, AI has changed and is continuing to change how lawyers engage professionally with the legal profession, as well as the manner in which lawyers access and use legal research in doing their daily work. AI’s effect on the way lawyers access legal materials is not limited to where they search, but the manner in which relationships between materials and relevance, authority and doctrinal pathways are developed.

3. MANUPATRA AS AN AI-ENABLED LEGAL RESEARCH PLATFORM

Manupatra has gradually transitioned from a traditional digital legal database to a new AI-powered legal research platform created specifically for the complex structure and principles of the Indian legal system. The design of its architecture has taken into consideration the way that precedents, statutory interpretation, and tribunal adjudication coexist in many jurisdictions that also use different languages. Rather than being like other generic legal search engines, Manupatra combines its structured databases of decisions from the Supreme Court, High Court and tribunals with statutory material, rules, circulars and commentaries, creating an overall legal authority that is not just made up of individual documents (Manupatra, n.d.-a).

One of the important aspects of the development of Manupatra is its ability to conduct searches based on both context and concepts. With traditional keyword searches, the results will often be fragmented as a result of differences in the way that legal concepts are stated in decisions. The Manupatra search interface allows users to search for cases based on the relevant legal issues, subject matter classifications and their relationship to doctrine, thus providing searches based on principles of natural language processing (NLP) and semantic searches. This enables users to search through cases for conceptually similar authorities rather than relying strictly on a word-for-word match, which is especially beneficial in India because of the different ways that similar cases are decided in multiple High Courts, but still, discuss similar concepts (Manupatra, n.d.-b).

Manupatra has another fundamental feature – Case Linking and Citation Tracking. This feature is based on the network analysis principles of AI. All of the judgments in Manupatra are linked via way of positive, negative or neutral citations, which can assist the user in determining the weight of precedential authority and how subsequent courts have treated that particular case. This function is similar to citation intelligence from an AI perspective, where you visually and structurally map the development of legal authority over time. Several recent Indian legal research studies have highlighted that citation tracking is important in systems where the precedential value of a case depends not only on its hierarchy but also on whether the case continues to be regularly adhered to or distinguished from (Sengupta, 2019).

Manupatra’s subject classification and taxonomy organization support AI-based information retrieval by limiting information noise for AI. Legal subjects and sub-subjects are curated according to Indian statutory and doctrinal categories. As a result, users can quickly find relevant materials, without needing to build elaborate query strings, by relying on the subject classification. This structured subject classification is useful for students conducting legal research, as it helps them approach their research thematically, as opposed to looking at particular cases (Tripathi, 2017).

Judicial trend mapping is one of the latest AI-aligned functionalities of Manupatra, enabling users to observe patterns of judicial decisions over time, by different courts, and for different topics. The tool gives researchers an aggregated view of similar types of decisions through theme and citation-based organization, as well as insight into how legal points of view have changed or remained steady. Indian research in judicial analytics suggests that trend-based tools can aid with strategic litigation planning and doctrinal analysis, especially within areas such as constitutional law and commercial law, where interpretive trends are important (Chandra, 2020).

Manupatra’s strategy: globally identifiable trend towards the use of AI in the preparation of legal documents. However, the majority of international companies using these technologies often focus on predictive analysis and predicting the outcome of litigation, whereas Manupatra’s focus has been more on the use of contextual authority mapping and doctrinal navigation, which align more closely with the Indian judicial culture/reality. Manupatra’s proprietary design includes substantial concerns due to the fact that the algorithms used to determine ranking and relevance of materials have not been disclosed to users; if users do not know how a particular authority is ranked as relevant or created an authority list, then it may significantly impact the individual’s research &/or arguments constructed from it. Consequently, legal scholars using Indian legal information technology have expressed concern over the effect that this type of absence may have on research outcomes and the types of authorities that are most visible to the user, as these will dictate argument construction and akademisch or academically interpreted (Sengupta, 2019).

Another major issue related to limited public access is the fact that Manupatra uses a subscription-based model and therefore, its advanced research capacity is limited to paying institutions and practitioners. This raises questions about equitable access for students at small institutions, independent researchers and self-represented litigants. Research on digital justice in India has found that while proprietary legal databases provide greater efficiency, they also risk creating even larger divisions in access to legal information unless other initiatives provide accessible and free public legal information (Chandra, 2020).

Although there are some concerns about its impact, Manupatra plays an important role in the way legal education, preparation of documents for use in court, how judges use the law, and research is done in the country. All of India’s law schools use it in their teaching of case analysis and statutory interpretation. Also, attorneys use it to provide a brief in connection with a case and identify relevant authority in an expeditious manner and judges and law clerks frequently reference it for ease of access to the appropriate authorative source. Additionally, researchers in academia benefit from having integrated access to the decisions of the court and the corresponding commentary, and in turn, this integration influences the way that legal knowledge is developed, cited, and issued in relation to the research conducted in the area of law in India (Tripathi, 2017).

Table 2: AI Features Integrated within Manupatra

Feature	Functional Description	Research Impact
Contextual Search	Concept-based retrieval aligned with legal issues	Improved relevance and precision
Case Linking	Citation-based interconnection of judgments	Better assessment of precedential value
Citation Tracking	Positive/negative treatment analysis	Informed authority evaluation
Subject Classification	Taxonomy-driven organization	Structured thematic research
Judicial Trend Mapping	Pattern identification across cases	Strategic and doctrinal insights

Manupatra’s use of Artificial Intelligence technology has improved the accuracy of legal research results and made access to relevant case law more contextually related. However, reliance on proprietary algorithms can create concerns about the neutrality of how lawyers and judges interpret legal information or use the information found in legal documents. Manupatra is a good example of how Artificial Intelligence can enhance efficiency and coherence in legal research inside of the Indian legal system while highlighting the need for transparency, accountability and ethical oversight in Artificial Intelligence assisted legal research tools.

4. ETHICAL, ACCESS, AND GOVERNANCE CHALLENGES IN AI-BASED LEGAL DATABASES

AI’s increasing presence in legal research databases is changing how legal knowledge is created, organized, and consumed. AI-enabled systems offer the ability to retrieve information faster, understand legal text in context, and analyze data more intelligently, but there are also severe ethical challenges posed by AI-based legal databases, particularly related to access and governance, which are crucial in jurisdictions like India where access to justice, judicial pluralism, and equality under the Constitution are the basis of the legal system.

AI powered legal databases raise ethical issues such as algorithmic bias. Algorithmic systems are trained on historical legal datasets such as case law, citation practices, and patterns of legal practice. These datasets are not neutral and instead reflect social hierarchies, institutional power, and dominant legal histories. Barocas & Selbst (2016) provide examples of how algorithmic systems developed using biased training datasets can perpetuate and exaggerate existing inequalities, even without any intentional bias by an algorithmic designer.  This applies to legal research databases as AI relevance ranking has the potential to favor frequently cited cases or judgments that come from institutions and status, and leave behind lower/infrequently cited cases, led to references for marginalized groups; as well as cases that refer to jurisdictional-specific types of law contrary to the claim made by the relevant party to the decision made by the legal system, or cases associated with unique situations associated to their geographic area. In determining this in an Indian context (where High Courts issue significantly different decisions with respect to the same legal issues) will ultimately materially impact the outcome of legal research.

An additional consideration in algorithmic bias relates to the exclusion/marginalization of dissenting judgment opinions. These legal opinions are significant in the legal system’s development, especially in constitutional democracies. In India particularly, many of the significant doctrines that have changed the legal framework were influenced by older dissenting opinions; but, when using AI-based citation and recommendation systems to compile legal research information, the majority opinions are often ranked the highest (because they are cited more frequently) and viewed as authoritative. As described by Ashley (2019), many of the characteristics needed to build a machine-learning model that identify relevance often rely on citation frequency and acceptance by other judges as relevance measures which, in turn, results in creative disagreement among judges legally, meaning that over time, these data-driven methods may continue to narrow the diversity of style through restricted interpretations and continue to suffice the creative use of law by judges. An additional difficulty has to do with how subscription-type services for AI lawyer databases divide up access (Some lawyers depend on being able to pay for AI databases in order to use them). Although these databases improve efficiency and accuracy, they are typically located in proprietary systems which are available only to people who have paid for access (Pasquale, 2015). This concentration of power has been stated by Pasquale as an example of how the concentration of the information on AI lawyer databases creates asymmetry, leading to less democratic accountability. In India, many lawyers are independent of each other (i.e. solo practitioners) and many people rely on lawyers for help getting legal representation. Many people depend on legal aid; therefore, if AI databases are not readily available to many people because of subscription services, this could lead to a disparity in the level of legal representation received by those seeking legal aid. The result is an inherent tension between improving technological advances and ensuring equal protection under the constitution of access to justice.

The issues around access to data were compounded by the monopolization of data. All legal judgments and statutes are public documents created by constitutional institutions, but when AI (Artificial Intelligence)- based legal databases aggregate, arrange and monetize public legal documents, they do so using proprietary analyses. This phenomenon, as described by Pasquale (2015), contributes to a wider “black box” society where only private entities may have access to algorithmic systems; this limits transparency, public oversight and adds to the problem of monopoly power of these technology companies. It also means that AI-enabled legal databases create extensive dependence on only a few sources of information (i.e. an AI-enabled legal database) thereby concentrating epistemic power (or authority), which in turn influences (or delivers) what the relevant law is within a community through opaque computational processes.

To fully appreciate the lack of governance attached to these AI-based legal databases is to understand their risks. One consistent critical issue around these AI systems is algorithmic opacity. Legal reasoning relies on being able to determine the explainability and justifiability of the authority relied upon; however, AI systems typically do not disclose the way relevance scores, recommendation algorithms and trend analyses are generated. Barocas and Selbst (2016) explain that because they lack transparency with respect to the data upon which AI systems make decisions, accountability cannot exist, as it would require identifying and challenging or correcting output from an AI system that has been developed and maintained by private entities for their financial return. Legal professionals in India are guided by their ethical duties to independently verify the sources of data they rely upon, and thus if they are unable to identify the underlying data used by AI systems to develop ‘algorithmically curated’ results, there is a significant and valid concern that lawyers will inappropriately rely on the AI-generated result as an independent source of verifying the law.

Concerns regarding standardization of legal reasoning arise with the use of AI-driven legal databases. When lawyers and judges utilize an AI-based legal database, they receive repeated exposure to the authorities that have been prioritized algorithmically; thus, these authorities may in turn influence the framing of arguments. According to Ashley (2019), AI-driven legal databases may direct users along the dominant doctrinal path and discourage exploration into authorities that are rarely cited but are nonetheless relevant to the context. In a plural legal system, such as India, where constitutional, statutory, and socio-customary norms overlap, this standardization effect will inhibit doctrinal innovation and limit the maintenance of alternative interpretative methods.

From the perspective of governance, the issues of ownership and regulatory oversight of legal AI database tools remain unresolved. There are no public governance arrangements for most AI-based legal research platforms; therefore there is a lack of transparency and little or no external auditing function for AI-based legal research platforms. Pasquale (2015) suggests that there should be stronger regulations for sectors that affect fundamental rights to maintain accountability and enhance public trust. Because there is no sectoral regulation for legal AI tools in India, the ethical responsibility for their use is relegated to the platform providers and end-user, compromising systemic safeguards.

Ethical challenges, access issues, and governance issues have a significant impact on the Indian legal system when using AI-based legal databases to support legal education, litigating practice, and judicial research through the development of these databases. The design choices made about these databases impact how legal knowledge is created and will therefore influence whether AI-based legal databases will create more equitable access to legal information rather than creating greater structural inequities due to the lack of ethical protection against bad faith, poor access policies, and lack of governance.

Table 3: Key Challenges of AI-Based Legal Databases

Dimension	Key Challenge	Implications
Ethical	Algorithmic bias	Reinforcement of historical inequalities
Interpretative	Marginalization of dissents	Reduced legal pluralism
Access	Subscription barriers	Unequal access to justice
Governance	Algorithmic opacity	Weak accountability
Structural	Data concentration	Dependence on private platforms

The above table shows that although AI increases the speed and ability to analyze legal research, there are still unresolved ethical and governance concerns that may result in decreased fairness, inclusivity, and diversity of interpretation in India’s legal system. Therefore, without ethical oversight or regulatory clarity, AI-based legal research databases could perpetuate the existing structural inequalities found in the justice system instead of creating equal access to legal information.

5. CONCLUSION

The research found that Manupatra has developed a notable junction between artificial intelligence (AI) and legal information systems within the backdrop of Indian legal research. The research also found that by incorporating AI-enhanced tools into its legal databases, Manupatra had vastly improved research speed, accuracy, and depth through the ability to perform contextual searching, intelligent case-linking, and structured navigation of large volumes of judicial and statutory material, which address many of the issues created by the rapid growth of legal information and limitations of traditional keyword-based research techniques.

The research also showed that the application of AI technology within legal research tools raises important issues that cannot be ignored. Among the central issues includes transparency of algorithms, disparity in access to proprietary information, and ethical governance; thus, it is clear that while AI-enhanced research tools can lead to more informed reasoning about the law, the opaque nature of their operations and concentration on subscription-based platforms has the potential to reinforce information inequality within the legal profession. In addition, relying on algorithmic rankings and recommendations has raised concerns regarding the neutrality of legal interpretation, marginalizing alternative judicial opinions, and the homogenisation of legal reasoning.

The findings of the research show how Manupatra has grown to indicate both the potential of artificial intelligence in legal research as well as the existing friction to using AI for legal research. AI has not only changed the way that legal research has been done from simply finding information to also interpreting and analyzing information, bei ng both a retrieval process as well as an interpretive and analytical process. However, the current lack of strong ethical safeguards and governance mechanisms around the use of AI may potentially undermine fundamental concepts of constitutional rights such as fairness, equality of access to justice, and pluralism. Therefore, the conclusion is that technological advancements alone are not enough; AI must also be developed in an ethical manner, maintained with accountability, and offer equal access to all users within the technology to accomplish their similar respective roles in providing justice.

Recommendations

Through the completion of the study on possible ethical and institutional foundations of Artificial Intelligence (AI) utilization within Legal Research Platforms, the following recommendations were made to enhance the establishment of ethical and institutional foundations for all types of legal research platforms enabled by AI technology. 

The creation of “transparent” AI explanation mechanisms in all legal database systems will provide the user with an understanding of how their relevance rankings, recommendations, and trend analyses were developed so that they can utilize those results more effectively, while holding themselves accountable as professionals.

The establishment of regulatory frameworks governing ethical access to use of AI technology in legal databases was identified as a necessity. Clear and standard regulations defining what constitutes an appropriate method to mitigate bias, explain capabilities, & provide accountability will create a collective standard by which all companies supplying legal research platforms can operate, thereby limiting each company’s reliance upon self-regulatory discretion to provide those solutions.

The establishment of hybrid access models (i.e.: providing both fee-based and limited-fee access for public and academic users of AI technology through legal research platforms) would provide greater access for the general public and the academic community to legal information thereby removing some types of informational inequality.

The stakeholders recommended that efforts be made to educate legal professionals about how to use AI appropriately through both training programs and by integrating AI into the law school curricula. This will provide lawyers, judges, and law students the ability to evaluate AI tools in a critical way instead of uncritically relying upon those tools.

Lastly, periodic audits of AI algorithms were recommended to ensure that they are neutral, inclusive, and consistently aligned with constitutional values. Periodic evaluations will allow for bias to be identified and corrected, and will help maintain public confidence in AI-enabled legal research systems.

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